TWI872163B - Method for producing laminate and laminating apparatus - Google Patents

Abstract

Provided is a method for producing a laminate and a laminating apparatus that can easily control the amount and direction of warpage of the laminate after laminating having an optical display panel and an optical film. A method for producing a laminate 300 including an optical display panel 100 and an optical film 200, the method including: pressing a laminate 300 including an optical display panel 100 and an optical film 200 between a pair of nip rolls 21 and 22 rotating, in which in the pressing, a warpage is applied to the laminate 300 so as to be along the surface of one nip roll 21.

Description

Laminated body manufacturing method and bonding device

The present invention relates to a manufacturing method and bonding device for a multilayer body used in optical display devices such as liquid crystal displays.

Until now, optical films such as polarizing plates have been bonded to optical display panels such as liquid crystal panels to obtain laminated bodies.

(Prior technical literature) (Patent Literature)

Patent document 1: Japanese Patent Publication No. 2013-137538

However, for example, optical display panels such as liquid crystal panels will warp in the laminated body after lamination due to residual stress of the optical display panel and the optical film during lamination, shrinkage and expansion of the optical film over time, etc. The larger the optical display panel, the more significant the warp tendency will be. As for a method for solving this warp problem, a method of pre-warping the optical display panel slightly in the opposite direction of the aforementioned warp direction can be cited.

The purpose of the present invention is to provide a method for manufacturing a laminate and a bonding device, which can easily control the curvature and direction of the laminate having an optical display panel and an optical film after bonding.

The manufacturing method of the laminate of the present invention is to manufacture a laminate having an optical display panel and an optical film, and the manufacturing method comprises: a pressing step of pressing the laminate having the optical display panel and the optical film between a pair of rotating rollers;

In the pressing step, the laminate is given a curvature along the surface of the roller on one side.

Here, the above method may be further equipped with: a step of transporting the optical display panel toward the above pair of rollers by an upstream horizontal transport mechanism; and

The step of transporting the aforementioned layered mass discharged from the aforementioned pair of rollers by means of a downstream horizontal transport mechanism;

The rotating shafts of the aforementioned pair of rollers are arranged to be separated in the vertical direction;

In the pressing step, the height of the portion of the laminated body clamped by the pair of rollers is made lower or higher than the height of the upper surface of the upstream horizontal transport mechanism and the height of the upper surface of the downstream horizontal transport mechanism, thereby imparting a warp to the laminated body.

In addition, in the above method, the above-mentioned warp may not be imparted to the above-mentioned laminated body before the front end portion of the above-mentioned laminated body in the moving direction reaches the above-mentioned downstream horizontal transport mechanism;

After the front end of the aforementioned laminated body in the moving direction reaches the aforementioned downstream horizontal transport mechanism, the aforementioned laminated body is given the aforementioned curvature;

And while the rear end of the aforementioned optical display panel in the moving direction is still supported on the upper surface of the aforementioned upstream horizontal transport mechanism, the aforementioned warp is eliminated.

In addition, in the above method, the upstream side horizontal transport mechanism and the downstream side horizontal transport mechanism can be roller conveyors respectively.

In addition, the diameter of the aforementioned roller on one side may be larger than the diameter of the aforementioned roller on the other side.

In addition, the optical film may be a polarizing plate, and in the laminate pressed between the rollers, the direction of the transmission axis of the polarizing plate and the axis of the pair of rollers may be arranged to be parallel to each other.

In addition, the surface of the optical display panel may have a rectangular shape, and in the laminate pressed between the rollers, the direction of the transmission axis of the polarizing plate and the direction of the short side of the surface of the optical display panel may be arranged to be parallel to each other.

In addition, the optical display panel may be a liquid crystal panel, and the polarizing plate may be bonded so that the transmission axis of the polarizing plate is approximately parallel to the short side direction of the liquid crystal panel. In addition, the polarizing plate may be bonded to the TFT side of the liquid crystal panel.

The bonding device of the present invention comprises: a pair of rollers for pressing the laminate of the optical display panel and the optical film; and a warp imparting mechanism for imparting warp to the laminate along the surface of one of the rollers.

Here, the rotating shafts of the aforementioned pair of rollers can be configured to be separated in the up and down directions;

The aforementioned curvature imparting mechanism may have:

The upstream horizontal transport mechanism can transport the optical display panel on the aforementioned pair of rollers;

The downstream horizontal transport mechanism can transport the aforementioned optical display panel and optical film laminate discharged from the aforementioned pair of rollers; and

The positioning mechanism can position the position of the pair of rollers so that the height of the portion of the stacked body clamped by the pair of rollers is lower or higher than the height of the stacked body before being transported by the upstream horizontal transport mechanism and the height of the stacked body before being transported by the downstream horizontal transport mechanism.

In addition, the above-mentioned bonding device may be further equipped with a control unit, which can control the above-mentioned positioning mechanism to:

Before the front end of the aforementioned laminated body in the moving direction reaches the aforementioned downstream horizontal transport mechanism, the height of the portion of the aforementioned laminated body clamped by the aforementioned pair of rollers is maintained at the same height as the upper surface of the aforementioned upstream horizontal transport mechanism and the upper surface of the aforementioned downstream horizontal transport mechanism;

After the front end of the stacked body in the moving direction reaches the upstream horizontal transport mechanism, the position of the pair of rollers is changed relative to the upstream horizontal transport mechanism and the downstream horizontal transport mechanism, so that the height of the portion of the stacked body clamped by the pair of rollers is lower or higher than the upper surface of the upstream horizontal transport mechanism and the upper surface of the downstream horizontal transport mechanism;

And while the rear end of the optical display panel in the moving direction is still supported on the upper surface of the upstream horizontal transport mechanism, the height of the portion of the laminated body clamped by the pair of rollers is returned to the same height as the upper surface of the upstream horizontal transport mechanism and the upper surface of the downstream horizontal transport mechanism.

In addition, the aforementioned upstream side horizontal transport mechanism and downstream side horizontal transport mechanism can be roller conveyors respectively.

In addition, the diameter of the aforementioned roller on one side may be larger than the diameter of the aforementioned roller on the other side.

In addition, the optical film may be a polarizing plate, and in the laminate pressed between the rollers, the direction of the transmission axis of the polarizing plate and the axis of the pair of rollers may be arranged to be parallel to each other.

In addition, the surface of the optical display panel may have a rectangular shape, and in the laminate pressed between the rollers, the direction of the transmission axis of the polarizing plate and the direction of the short side of the surface of the optical display panel may be arranged to be parallel to each other.

In addition, the aforementioned optical display panel may be a liquid crystal panel, and the aforementioned polarizing plate may be attached to the TFT side of the aforementioned liquid crystal panel.

According to the present invention, a method for manufacturing a laminate and a bonding device are provided, which can easily control the curvature and direction of the laminate having an optical display panel and an optical film after bonding.

1: Laminating device

5: The mechanism of curvature endowment

10: Upstream roller conveyor (upstream horizontal transport mechanism)

10a: Transport roller

10a1: Roller

21,22: Roller

21a,22a: Rotation axis

30: Polarizing film roll

40: Downstream roller conveyor (downstream horizontal transport mechanism)

40a: Transport roller

40a1: Roller

50: Positioning mechanism

60: Control Department

80:Reel

100: Liquid crystal panel (optical display panel)

100A: First transparent substrate

100B: Liquid crystal layer

100C: Second transparent substrate

100CF: Color filter side

100TFT: TFT side

200: Polarizing plate (optical film)

200A: Protective film

200B: Polarizing element layer

200C: Protective film

200D: Adhesive/adhesive layer

210: Peeling membrane

300: Layered body

400A: Front-end fixed deflection

400B: Fixed rear end curvature

A: Short side of the front end

B: Short side of the rear end

CV1: Distance

CV2: Distance

F: Front end side end

H1: Height

H1min: height

H2: Height

H3: Height

L1: Length

L2: Length

L3: Length

L4: Length

Lmax: length

P: Part

R: Rear end

S: horizontal plane

FIG. 1(a) is a schematic diagram showing the cross-sectional structure of a liquid crystal panel (optical display panel) of an embodiment of the present invention, and FIG. 1(b) is a schematic diagram showing the cross-sectional structure of a polarizing plate (optical film) of an embodiment of the present invention.

Figure 2 is a schematic diagram of a bonding device according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a bonding device of an embodiment of the present invention, and is a diagram following the state of FIG. 2.

Figure 4 shows the relationship between the length L and H1’ in the transport direction of the liquid crystal panel.

Figures 5(a) to 5(c) are schematic end views of various laminates after attachment, viewed from the short side direction (horizontal direction is the long side direction).

FIG6 is a schematic diagram showing an overview of the fixed warp amount of the embodiment, FIG6(a) shows the fixed warp amount at the front end, and FIG6(b) shows the fixed warp amount at the rear end.

The following is a description of an embodiment of the present invention with reference to the drawings. The dimensions of the drawings are arbitrary and are used to illustrate the invention.

In this embodiment, the case where the optical display panel is a liquid crystal panel and the optical film is a polarizing plate is taken as an example to explain the method and device for bonding the liquid crystal panel and the polarizing plate. First, the liquid crystal panel 100 and the polarizing plate 200 to be bonded are explained with reference to FIG. 1(a) and FIG. 1(b).

As shown in FIG. 1( a ), the liquid crystal panel 100 may include: a first transparent substrate 100A, a liquid crystal layer 100B, and a second transparent substrate 100C in sequence. The typical materials of the first transparent substrate and the second transparent substrate of the liquid crystal panel may be glass.

In this embodiment, the shape of the liquid crystal panel 100 is a rectangle.

There is no specific limit to the size of the rectangle of the LCD panel 100, and the length of the long side can be 20 to 2600 mm. In particular, since the larger the LCD panel, the more likely it is to have a warping problem, the length of the long side is more suitable to be 1200 mm or more.

There is no specific limit to the thickness of the liquid crystal panel 100, for example, it can be about 0.5 to 5 mm, preferably 1 to 5 mm.

As shown in FIG. 1( b ), the polarizing plate 200 may include: a pair of protective films 200A and 200C, a polarizing element layer 200B disposed between the pair of protective films 200A and 200C, and an adhesive (pressure sensitive adhesive, also called pressure sensitive adhesive)/adhesive layer 200D disposed on one of the protective films 200C.

The protective films 200A and 200C can be, for example, triacetyl cellulose film (hereinafter also referred to as "TAC"), cycloolefin film, acrylic and other polarizing plate technology fields that are commonly used. In addition, FIG. 1(b) shows the cross-sectional structure of a polarizing plate having protective films 200A and 200C on both sides of the polarizing element layer 200B, but the present invention can also be applied to a polarizing plate having a protective film only on one side of the polarizing element layer (single-sided protected polarizing plate). Although not shown, a single-sided protected polarizing plate usually has an adhesive/bonding agent layer 200D directly provided on the side of the polarizing element layer 200B that does not have a protective film.

The polarizing element forming the polarizing element layer 200B may be a polyvinyl alcohol film dyed with a dichroic pigment such as iodine, and may be manufactured by uniaxial stretching. Hereinafter, the polyvinyl alcohol film dyed with a dichroic pigment such as iodine as described above will also be referred to as "PVA".

The adhesive/bonding agent layer 200D may be, for example, an acrylic resin layer.

There is no specific limit to the thickness of the polarizing plate 200, and it can be, for example, 25 to 250 μm.

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

FIG2 is a schematic diagram of a laminating device 1 of the first embodiment of the present invention. The laminating device 1 of the present embodiment mainly comprises: an upstream side roller conveyor 10, a pair of rollers 21, 22, a downstream side roller conveyor 40, a positioning mechanism 50 for adjusting the height of the pair of rollers 21, 22, and a control unit 60 for controlling the positioning mechanism 50, and laminating the liquid crystal panel 100 and the polarizing plate 200 to manufacture the laminate 300. The pair of rollers 21, 22, the upstream side roller conveyor 10, the downstream side roller conveyor 40, and the positioning mechanism 50 constitute the warp imparting mechanism 5.

The upstream roller conveyor (upstream horizontal transport mechanism) 10 has a plurality of transport rollers 10a, and the rotation axes of the transport rollers are arranged in the horizontal direction and arranged to be parallel to each other in the horizontal plane. The upstream roller conveyor 10 transports the liquid crystal panel 100 supplied from the supply source (not shown) along the horizontal direction (from left to right in FIG. 2) on the upper surface of the upstream roller conveyor, and supplies it to a pair of rollers 21 and 22.

In this embodiment, the upstream roller conveyor 10 transports the liquid crystal panel 100 with its two rectangular surfaces facing up and down and the short sides of the rectangular surfaces parallel to the axes of the rollers 21 and 22.

The rollers 21 and 22 have rotating shafts 21a and 22a, respectively. The rotating shafts 21a and 22a are arranged to be separated in the vertical direction. In addition, the rotating shafts 21a and 22a are arranged to be parallel to each other and parallel to the rotating shaft of the transport roller 10a of the upstream roller conveyor 10. There is no specific restriction on the surface material of the rollers, and rubber, metal, etc. can be used. However, from the perspective of not significantly damaging the liquid crystal panel, rubber is more suitable.

In this embodiment, the diameter of the upper roller 21 is set to be larger than the diameter of the lower roller 22. Thus, the laminate 300 can be given an appropriate curvature along the upper roller 21 with a larger diameter, and the laminate 300 can be fully pressed by the lower roller 22 with a smaller diameter.

The diameter of the upper roller 21 may be 30 to 300 mm. In addition, the diameter of the lower roller 22 may be 10 to 100 mm.

The laminate 300 is transported from the upstream side (left side) to the downstream side (right side) in FIG. 2 , so the upper roller 21 can move counterclockwise in FIG. 2 , while the lower roller 22 can move clockwise. A pair of rollers can be driving rollers or driven rollers, and preferably at least one of them is a driving roller.

The polarizing plate 200 is supplied from the polarizing plate roll 30 to the roller 22 on the lower side. In this embodiment, the direction of the penetration axis of the polarizing plate 200 is configured to be parallel to the rotation axis of the rollers 21 and 22. That is, the direction of the absorption axis of the polarizing plate is parallel to the conveying direction of the liquid crystal panel. The polarizing plate 200 is attached to the liquid crystal panel 100 between the rollers 21 and 22 to obtain a laminate 300 including the liquid crystal panel 100 and the polarizing plate 200, and is discharged to the downstream side.

Here, the polarizing plate 200 is supported on the release film 210, so that the adhesive/adhesive layer is protected, and the polarizing plate 200 is only half-cut according to the size of the liquid crystal panel 100 and is transported by the lower roller 22, and the release film 210 is recovered to the reel 80 after the polarizing plate is attached. By using the release film 210 in this way, foreign matter can be prevented from being attached to the adhesive/adhesive layer of the polarizing plate 200.

Although not shown, a pair of rollers 21 and 22 are provided with a pressure imparting mechanism so that one roller presses the other roller with a predetermined pressure. In this way, the laminate 300 supplied between the pair of rollers 21 and 22 can be squeezed from both sides in the thickness direction, pressing the liquid crystal panel 100 and the polarizing plate 200 to make them close.

The pressing pressure can be appropriately set according to the required warping amount of the laminate 300, the characteristics of the liquid crystal panel 100 and the polarizing plate 200, etc., for example, it can be set to 0.1 to 0.7 MPa.

The downstream roller conveyor (downstream horizontal transport mechanism) 40 has a plurality of transport rollers 40a, and the rotation axes of the transport rollers 40a are arranged in the horizontal direction and arranged to be parallel to each other in the horizontal plane. The downstream roller conveyor 40 transports the laminate 300 discharged from a pair of rollers 21 and 22 along the upper surface in the horizontal direction (from left to right in FIG. 2). The obtained laminate 300 is supplied to the subsequent assembly process of the liquid crystal display.

The positioning mechanism 50 can move the position of a pair of rollers 21 and 22 in the up-down direction. As shown in FIG2 , the positioning mechanism 50 can make the height H1 of the portion P of the laminate 300 sandwiched between the pair of rollers 21 and 22 be 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. Usually, the height H2 is the same as the height H3. Here, the positioning mechanism 50 can be in the form of positioning one of the rollers 21 and 22 and slidingly contacting the other roller, or can be in the form of controlling the positioning of both rollers 21 and 22.

Furthermore, as shown in FIG3 , the positioning mechanism 50 can make the height H1 of the portion P of the laminate 300 clamped between a pair of rollers 21 and 22 lower than 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.

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

Here, the height H2 of the upper surface of the upstream roller conveyor 10 can also be referred to as the height of the bottom surface of the liquid crystal panel 100 horizontally transported by the upstream roller conveyor 10, and the height H3 of the upper surface of the downstream roller conveyor 40 can also be referred to as the height of the bottom surface of the laminate 300 horizontally transported by the downstream roller conveyor 40. In addition, the height H1 of the portion P of the laminate 300 clamped between a pair of rollers 21 and 22 refers to the height of the lowest portion of the bottom surface of the portion P clamped between a pair of rollers 21 and 22 in the laminate.

When the distance in the conveying direction between the rotating shafts 21a, 22a of a pair of rollers 21, 22 and the rotating shaft of the roller 10a1 closest to the rollers 21, 22 in the upstream roller conveyor 10 is set to CV1, and the distance in the conveying direction between the rotating shafts 21a, 22a of a pair of rollers 21, 22 and the rotating shaft of the roller 40a1 closest to the rollers 21, 22 in the downstream roller conveyor 40 is set to CV2, there is no specific restriction on the distances CV1 and CV2, but it is preferably about two to five times the diameter of the roller on the larger diameter side of the pair of rollers 21, 22. In addition, the length of the liquid crystal panel 100 in the transport direction (for example, the length of the long side) exceeds CV1+CV2, usually more than twice.

The control unit 60 controls the positioning mechanism 50 to move the pair of rollers 21 and 22 up and down, so that the height H1 of the portion P of the laminate 300 clamped between the pair of rollers 21 and 22 changes. Specifically, in this embodiment, the control unit 60 changes the height H1 of the portion P up and down when a liquid crystal panel 100 passes between the pair of rollers 21 and 22.

Specifically, the control unit 60 can change the height H1 as shown in FIG4. In FIG4, the horizontal axis is the length of the liquid crystal panel 100 in the conveying direction (for example, the long side direction or short side direction of the rectangle), the length L=0 is the end of the starting side of the bonding (the front end side of the conveying direction), and the length Lmax is the end of the end side of the bonding (the rear end side of the conveying direction). When 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 are used as the reference, the height H1' of the longitudinal axis is the height H1 of the portion P of the laminate 300 clamped between a pair of rollers 21 and 22, and the negative meaning is lower than the height H2 and H3.

Height H1 is maintained at 0 from length 0 (bonding start position) to length L1, decreases from length L1 to length L2, and is maintained at a height H1min lower than heights H2 and H3 from length L2 to length L3, increases from length L3 to length L4, and is maintained at 0 from length L4 to 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 500mm, L2-L1 can be 100 to 2500mm, Lmax-L4 can be 10 to 500mm, and L4-L3 can be 10 to 500mm.

The above values are preferred for height H1min.

In other words, the control unit 60 controls the positioning mechanism 50 to maintain the height H1 of the portion P of the laminate 300 clamped by the pair of rollers 21 and 22 at the same height as the height H2 of the upper surface of the upstream side roller conveyor 10 and the height H3 of the upper surface of the downstream side roller conveyor 40 until the front end side end F of the laminate 300 formed between the pair of rollers 21 and 22 contacts the upper surface (a portion) of the downstream side roller conveyor 40.

Furthermore, after the front end of the laminate 300 contacts the upper surface (partially) of the downstream side roller conveyor 40, the control unit 60 controls the positioning mechanism 50 in a state where the rear end R of the laminate 300 contacts the upper surface (partially) of the upstream side roller conveyor 10, and controls the positioning mechanism 50 so that the height H1 of the portion P of the laminate 300 clamped by a pair of rollers 21 and 22 is lower than the height H2 of the upper surface of the upstream side roller conveyor 10 and the height H3 of the upper surface of the downstream side roller conveyor 40.

Furthermore, the control unit 60 controls the positioning mechanism 50 to return the height of the portion P of the laminate 300 clamped by the pair of rollers 21 and 22 to the same height as the height H2 of the upper surface of the upstream side roller conveyor 10 and the height H3 of the upper surface of the downstream side roller conveyor 40, and then maintains the same height before the laminate 300 is discharged from between the pair of rollers.

Here, the timing of the height change of the control unit 60 can be realized by using appropriate sensors to detect the front side end F and the rear side end R of the transported liquid crystal panel 100 to know the speed of the conveying line.

Next, the manufacturing method of the optical display device of the embodiment of the present invention is described.

First, as shown in FIG2 , the liquid crystal panel 100 is supplied between a pair of rollers 21 and 22 by the upstream roller conveyor 10, and the polarizing plate 200 supplied by the polarizing plate roll 30 is supplied between the pair of rollers 21 and 22 along the surface of the lower roller 22, and the laminated body 300 formed by laminating the liquid crystal panel 100 and the polarizing plate 200 is pressed by the pair of rollers 21 and 22. In this way, the adhesive/adhesive layer 200D of the liquid crystal panel 100 and the polarizing plate 200 are in contact and sequentially bonded from the front end F to the rear end R.

Here, the control unit 60 controls the positioning mechanism 50 to make the height H1 of the portion P of the laminate 300 clamped by a pair of rollers 21 and 22 the same as the height H2 of the upper surface of the upstream side roller conveyor 10 and the height H3 of the upper surface of the downstream side roller conveyor 40 before the front end side end F of the laminate 300 in the moving direction reaches the upper surface of the downstream side roller conveyor 40, without giving the laminate 300 a warp. In this way, damage to the front end side end F of the laminate 300 is suppressed.

After that, the laminate 300 is continuously transported. When the front end F of the laminate 300 in the moving direction reaches the downstream roller conveyor 40, the control unit 60 controls the positioning mechanism 50 to make the portion P of the laminate 300 lower than the height H2 of the upper edge of the upstream roller conveyor 10 and the height H3 of the upper edge of the downstream roller conveyor 40. In this way, the laminate 300 is given a warp along the upper roller 21, and in the state of being given a warp, the liquid crystal panel 100 and the polarizing plate 200 are bonded by a pair of rollers 21 and 22.

After that, the stacked body 300 is further transported, and while the rear end R of the liquid crystal panel 100 in the moving direction is supported on the upper surface of the upstream side roller conveyor 10, the control unit 60 controls the positioning mechanism 50 so that the height of the portion P of the stacked body 300 clamped by a pair of rollers 21 and 22 returns to the same height as the upper surface of the upstream side roller conveyor 10 and the upper surface of the downstream side roller conveyor 40, so that the warp is eliminated. In this way, damage to the rear end R of the stacked body 300 is suppressed.

In this way, the liquid crystal panel 100 and the polarizing plate 200 are bonded together in a warped state to complete the formation of the laminate 300.

Then, in response to demand, a liquid crystal display (optical display device) can be obtained by combining the laminate 300 with a backlight and other processes.

Next, the function of this implementation is explained.

In the manufacture of liquid crystal displays, polarizing plates are attached to both sides of the liquid crystal panel, and the transmission axes of the two polarizing plates are arranged perpendicular to each other (crossed nicols). In addition, usually, the polarizing element of the polarizing plate is manufactured by stretching, so the polarizing plate is easy to shrink in the direction perpendicular to the transmission axis, that is, the polarizing plate is easy to shrink in the direction parallel to the absorption axis.

In this embodiment, the transmission axis of the polarizing plate 200 is parallel to the rotation axis 21a, 22a between a pair of rollers 21, 22, that is, orthogonal to the conveying direction of the laminate 300. In the previous method, as shown in FIG. 2, the liquid crystal panel 100 and the polarizing plate 200 are bonded under the condition of maintaining a non-warping state between a pair of rollers 21, 22.

Specifically, when the liquid crystal panel 100 and the polarizing plate 200 are bonded together so that the short side direction of the liquid crystal panel 100 is parallel to the transmission axis of the polarizing plate 200, in other words, the long side direction of the liquid crystal panel 100 is parallel to the absorption axis of the polarizing plate 200, after bonding, the polarizing plate 200 will shrink along the absorption axis, so that the laminate 300 after bonding will be easily warped as shown in FIG5(a) so that the surface (lower surface) of the polarizing plate 200 becomes concave, and the surface of the liquid crystal panel 100 (the upper surface opposite to the bonding surface of the polarizing plate 200) becomes convex. Here, in FIG5(a) to (c), the horizontal direction is the long side direction of the laminate 300 and the liquid crystal panel 100. If there is such warp, it will cause light leakage and other defects in the LCD display after the backlight is assembled, so there is a need to reduce the warp.

In particular, as shown in FIG5(b), when the polarizing plate 200 having an absorption axis parallel to the long side direction is attached to the TFT side 100TFT of the liquid crystal panel 100, it is not desirable that the color filter side 100CF of the liquid crystal panel 100 becomes convex as shown in FIG5(a), and the situation without warping as shown in FIG5(b) is preferred. However, there is also a situation where the situation warping in the opposite direction as shown in FIG5(c) is preferred.

According to the present embodiment, when the laminate 300 is pressed between a pair of rollers, as shown in FIG3 , the laminate 300 is given a warp along the surface of one roller 21. That is, the laminate 300 is pressed and bonded in a state where the surface (lower surface) of the polarizing plate 200 is convex and the surface (upper surface) opposite to the bonding surface of the polarizing plate in the liquid crystal panel 100 is concave. In this way, the stress between the liquid crystal panel 100 and the polarizing plate 200 of the laminate 300 can be controlled, so that the shape of the laminate 300 after bonding will not be warped as shown in FIG5(a), but will be a shape with the same warp direction as FIG5(a) but with reduced warp, or a shape without warp as shown in FIG5(b), or a shape with warp in the opposite direction as shown in FIG5(c).

Specifically, the warp control of the laminated body 300 can be performed by adjusting the warp amount of the laminated body 300 in the pressing step between a pair of rollers 21 and 22 as shown in FIG3. For example, when H1min is lower than H2 and H3 and the warp is larger, the warp can be changed in sequence as shown in FIG5(a), FIG5(b), and FIG5(c).

The present invention is not limited to the above-mentioned implementation forms, and various variations can also be implemented.

For example, the rotation axes 21a and 22a of a pair of rollers 21 and 22 do not need to be parallel to the short side of the rectangle of the LCD panel 100 when attached, but can be parallel to the long side of the rectangle, or can be inclined to the long side or short side of the rectangle.

In addition, in the above-mentioned implementation, the transmission axis of the polarizing plate 200 during attachment is set to be parallel to the rotation axes 21a and 22a of a pair of rollers 21 and 22, but the direction of the transmission axis is arbitrary and can also be perpendicular to the rotation axes 21a and 22a of a pair of rollers 21 and 22, even in an inclined direction.

In addition, as for the horizontal transport mechanism, in addition to the roller conveyor, a belt conveyor can also be used.

In addition, in the above-mentioned implementation form, as shown in FIG. 4, when the laminate is not supported by both the upstream side roller conveyor and the downstream side roller conveyor, the height H1 is made the same as the height H2 and H3. However, when the difference between H1 and H2 and H3 is small, H1 can be fixed in a state different from H2 and H3.

In addition, the above-mentioned implementation mode describes the case where the polarizing plate is attached to the TFT side of the liquid crystal panel, but it can also be applied to the case where the polarizing plate is attached to the color filter side of the liquid crystal panel.

In addition, the shape of the LCD panel does not need to be rectangular, but can also be circular, elliptical, and other shapes.

Furthermore, in the above-mentioned embodiment, the pre-cut polarizing plate is attached to the long supporting film, so that the liquid crystal panel, the polarizing plate, and the supporting film are pressed together to supply the polarizing plate, but other methods can also be used to supply. For example, the polarizing plate cut by a cutter or the like can be peeled off from the supporting film and then attached to the liquid crystal panel and supplied between a pair of rollers.

In addition, as long as the polarizing plate includes a polarizing element layer, there is no specific restriction on the layered structure.

In addition, in the above-mentioned implementation form, the optical display panel adopts a liquid crystal panel, but the above-mentioned implementation form can also be applied to optical display panels other than liquid crystal panels, such as organic EL panels. The thickness, shape, and size of the optical display panel other than the liquid crystal panel can also be the same as that of the liquid crystal panel.

The organic EL panel may have: a first transparent substrate, an organic light emitting diode (OLED) layer, and a second transparent substrate. The first transparent substrate may be a substrate on which a TFT is mounted.

In addition, the optical film attached to the optical display panel is not limited to linear polarizers, but can also be applied to various films such as circular polarizers and elliptical polarizers, phase difference plates, brightness enhancement films, complex refraction control films, and anti-reflection films. Even if the optical film itself does not show anisotropic shrinkage, it can be given warp when attached, thereby controlling the warp after attachment.

Furthermore, in the above-mentioned embodiment, a warp imparting mechanism 5 having an upstream roller conveyor 10, a downstream roller conveyor 40, a pair of rollers 21, 22, and a pair of roller positioning mechanism 50 is used to impart warp to the pair of rollers 21, 22 by moving downward. However, the method of imparting warp to the laminate along the surface of the pair of rollers is not limited to this.

For example, in the pressing step, the height of the portion P of the laminate 300 clamped by a pair of rollers 21 and 22 is higher than 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. When the portion P of the laminate 300 moves along the lower roller 22 by gravity, the laminate can also be warped.

In addition, it is also possible to transport the optical display panel at an angle rather than horizontally.

In addition, in the above-mentioned embodiment, the diameters of a pair of rollers 21 and 22 are different from each other, and a single pair of rollers 21 and 22 can also be implemented with the same diameter. In addition, when the height H1 of the part P is moved to a lower level than the heights H2 and H3 to give a warp, the diameter of the upper roller is preferably larger, and when the height of the part P is moved to a higher level than the heights H2 and H3 to give a warp, the diameter of the lower roller is preferably larger.

In addition, a single roller may be arranged before and after a pair of rollers 21 and 22 to replace the horizontal conveying mechanism having a plurality of rollers, such as the upstream side roller conveyor 10 and the downstream side roller conveyor 40, to impart the warp.

(Implementation example)

(Examples 1 to 6 and Comparative Example 1)

Use the bonding device shown in Figures 2 and 3 to bond the liquid crystal panel to the polarizing plate.

LCD panel: thickness 1.0mm, rectangular long side 1660mm, short side 950mm

Polarizing plate layer structure: Adhesive layer (thickness 20μm)/TAC (thickness 60μm)/PVA (thickness 20μm)/TAC (thickness 60μm)

Here, TAC and PVA are bonded together via an adhesive layer, but the thickness of the adhesive layer is omitted.

The transmission axis of the polarizing plate is arranged to be parallel to the rotation axis of the roller, and the short side of the liquid crystal panel is arranged to be parallel to the rotation axis of the roller. The polarizing plate is attached to the TFT side of the liquid crystal panel.

Roller conditions: the diameter of the upper roller is 100mm, the diameter of the lower roller is 30mm. Here, the roller is made of rubber.

Table 1 shows: CV1, CV2, bonding pressure applied by a pair of rollers, bonding speed ratio, whether a pair of rollers are lowered during bonding, and the amount of lowering.

The bonding speed ratio refers to the ratio of the speed of the liquid crystal panel 100 to the speed of the polarizing plate 200.

In addition, regarding the drop in height H1 during bonding, according to Figure 4, it is set to L1=250mm, L2=350mm, L3=1240mm, and L4=1340mm.

The obtained warp amount of the laminate is shown in Table 1. Here, as shown in FIG6(a), the laminate 300 is placed on a horizontal plane S with the warped convex side facing downward, and the maximum floating amount of the bonded rear end side short side B of the bottom surface is measured as the fixed front end warp amount 400A when the bonded front end side short side A of the bottom surface of the laminate 300 is in contact with the horizontal plane S; and as shown in FIG6(b), the maximum floating amount of the bonded front end side short side A of the bottom surface is measured as the fixed rear end warp amount 400B when the bonded rear end side short side B of the bottom surface is in contact with the horizontal plane S. Here, the warp when the color filter side 100CF of the liquid crystal panel 100 shown in FIG5(a) is convex is defined as positive warp, and the warp when the TFT side 100TFT of the liquid crystal panel 100 shown in FIG5(c) is convex is defined as negative warp.

[Table 1]

According to the implementation example, it was confirmed that the curvature amount and direction of the laminate can be controlled.

1: Laminating device

5: The mechanism of curvature endowment

10: Upstream roller conveyor (upstream horizontal transport mechanism)

10a: Transport roller

10a1: Roller

21,22: Roller

21a,22a: Rotation axis

30: Polarizing film roll

40: Downstream roller conveyor (downstream horizontal transport mechanism)

40a: Transport roller

40a1: Roller

50: Positioning mechanism

60: Control Department

80:Reel

100: Liquid crystal panel (optical display panel)

200: Polarizing plate (optical film)

210: Peeling membrane

300: Layered body

P: Part

F: Front end side end

R: Rear end

H1: Height

H2: Height

H3: Height

CV1: Distance

CV2: Distance

Claims (16)

A method for manufacturing a laminate having an optical display panel and an optical film comprises: a pressing step, in which the laminate is formed by pressing and bonding the optical display panel and the optical film between a pair of rotating rollers; in the pressing step, the optical display panel to which the optical film is bonded is warped along the surface of one of the rollers. The manufacturing method of the laminate as described in claim 1 is further provided with: a step of transporting the optical display panel toward the pair of rollers by an upstream horizontal transport mechanism; and a step of transporting the laminate discharged from the pair of rollers by a downstream horizontal transport mechanism; the rotation axes of the pair of rollers are arranged to be separated in the vertical direction; in the pressing step, the height of the portion of the laminate clamped by the pair of rollers is made lower or higher than the height of the upper surface of the upstream horizontal transport mechanism and the height of the upper surface of the downstream horizontal transport mechanism, thereby imparting a warp to the optical display panel. A method for manufacturing a laminate as described in claim 2, wherein the optical display panel is not given the warp before the front end of the laminate in the moving direction reaches the downstream horizontal transport mechanism; and the optical display panel is given the warp after the front end of the laminate in the moving direction reaches the downstream horizontal transport mechanism; and the warp is eliminated while the rear end of the optical display panel in the moving direction is still supported on the upper surface of the upstream horizontal transport mechanism. A method for manufacturing a laminate as described in claim 2 or 3, wherein the upstream horizontal transport mechanism and the downstream horizontal transport mechanism are roller conveyors, respectively. A method for manufacturing a laminate as described in claim 2 or 3, wherein the diameter of the roller on one side is larger than the diameter of the roller on the other side. A method for manufacturing a laminate as described in claim 2 or 3, wherein the optical film is a polarizing plate, and in the laminate formed between the rollers, the direction of the transmission axis of the polarizing plate and the axis of the pair of rollers are arranged parallel to each other. A method for manufacturing a laminate as described in claim 6, wherein the surface of the optical display panel is rectangular in shape, and in the laminate to be formed between the rollers, the direction of the transmission axis of the polarizing plate and the direction of the short side of the surface of the optical display panel are arranged to be parallel to each other. The manufacturing method of the multilayer body as described in claim 6, 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 bonding device comprises: a pair of rollers for pressing and bonding an optical display panel and an optical film to form a laminate; and a warp imparting mechanism for imparting warp to the optical display panel to which the optical film is attached along the surface of one of the rollers. The bonding device as described in claim 9, wherein the rotation axes of the pair of rollers are arranged to be separated in the vertical direction; the warp imparting mechanism comprises: an upstream horizontal transport mechanism for transporting the optical display panel by the pair of rollers; a downstream horizontal transport mechanism for transporting the laminate of the optical display panel and the optical film discharged from the pair of rollers; and a positioning mechanism for positioning the pair of rollers so that the height of the portion of the laminate clamped by the pair of rollers is lower or higher than the height of the upper surface of the upstream horizontal transport mechanism and the height of the upper surface of the downstream horizontal transport mechanism. The laminating device as described in claim 10 is further provided with a control unit, which controls the positioning mechanism so that: before the front end side end portion of the laminate in the moving direction reaches the above-mentioned downstream horizontal transport mechanism, the height of the portion of the laminate clamped by the above-mentioned pair of rollers is maintained at the same height as the height of the upper surface of the above-mentioned upstream horizontal transport mechanism and the height of the upper surface of the above-mentioned downstream horizontal transport mechanism; and after the front end side end portion of the laminate in the moving direction reaches the above-mentioned downstream horizontal transport mechanism, the position of the above-mentioned pair of rollers is kept relative to the above-mentioned upstream horizontal transport mechanism. The transport mechanism and the aforementioned downstream horizontal transport mechanism are changed so that the height of the portion of the aforementioned laminated body clamped by the aforementioned pair of rollers is lower or higher than the height of the upper surface of the aforementioned upstream horizontal transport mechanism and the height of the upper surface of the aforementioned downstream horizontal transport mechanism; and while the rear end of the aforementioned optical display panel in the moving direction is still supported on the upper surface of the aforementioned upstream horizontal transport mechanism, the height of the portion of the aforementioned laminated body clamped by the aforementioned pair of rollers is returned to the same height as the height of the upper surface of the aforementioned upstream horizontal transport mechanism and the height of the upper surface of the aforementioned downstream horizontal transport mechanism. The laminating device as described in claim 10 or 11, wherein the upstream horizontal transport mechanism and the downstream horizontal transport mechanism are roller conveyors respectively. The bonding device as described in claim 10 or 11, wherein the diameter of the roller of one side is larger than the diameter of the roller of the other side. The laminating device as described in claim 10 or 11, wherein the optical film is a polarizing plate, and in the laminate formed between the rollers, the direction of the transmission axis of the polarizing plate and the axis of the pair of rollers are arranged to be parallel to each other. The bonding device as described in claim 14, wherein the surface of the optical display panel is rectangular in shape, and in the laminate formed between the rollers, the direction of the transmission axis of the polarizing plate and the direction of the short side of the surface of the optical display panel are arranged to be parallel to each other. The bonding device as described in claim 14, wherein the optical display panel is a liquid crystal panel, and the polarizing plate is bonded to the TFT side of the liquid crystal panel.

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