JP5002490B2 - Optical film pressurizer - Google Patents

Description

  The present invention relates to an optical film that is arranged so as to press-contact with a pressure roller of a stretching section configured to contact an optical film via the optical film, and to apply pressure to the optical film to be stretched The present invention relates to a pressure device.

Conventionally, a nip roll method has been widely used as a method for stretching an optical film. Some prior arts employ a configuration in which an optical film is guided to a stretching portion and stretched by a plurality of sets of nip rollers in which the ratio of peripheral speeds is appropriately set in the stretching portion (for example, Patent Documents). 1). The invention according to Patent Document 1 employs a stretching technique that takes advantage of the advantages of the dry stretching method and the wet stretching method when manufacturing an optical film by the nip roll method.
JP 2002-350638 A

  One important factor in stretching the optical film is to stabilize the force that holds the optical film at the nip portion of a plurality of sets of nip rollers that apply tension to the optical film. This holding force is represented by the product of the surface pressure per unit area in the nip portion, the area of the nip portion, and the friction coefficient between the roller and the optical film. For this reason, in order to stabilize the above-mentioned holding force, it is important to stabilize the surface pressure per unit area, the area of the nip portion, and the friction coefficient between the roller and the optical film.

  However, in the conventional technique, the area of the narrow nip portion may fluctuate due to the rotation of the roller, and the holding force of the optical film in the nip portion may not be stable. For this reason, it is preferable to increase the area of the nip portion, but it was difficult to effectively increase the area of the nip portion even if conventional design changes such as an increase in the diameter of the roller and improvement of the surface member of the roller were performed. .

  An object of the present invention is to provide an optical film pressurizing apparatus that makes it possible to stably hold an optical film to be stretched.

  The optical film pressurizing apparatus according to the present invention is configured to press-contact with a pressurizing roller of a stretching unit configured so that an optical film to be stretched comes into contact with the optical film via the optical film. This optical film pressurizing apparatus includes a belt unit and a unit support. The unit support is configured to support the belt unit. For example, in the stretching system that employs the dry stretching method, the unit support portion is attached to a frame that defines the stretching portion. In the stretching system that employs the wet stretching method, the unit support portion is attached to a bathtub provided in the stretching portion. As long as the unit support part is stably fixed to the extending part while supporting the belt unit, the shape, structure, size, and the like are not particularly limited.

  The belt unit is supported by the unit support portion so as to be in pressure contact with the pressure roller. The belt unit includes a shaft, a plurality of guide rollers, an endless belt, and an end fixing member. An axis | shaft is horizontally arrange | positioned so that it may orthogonally cross the advancing direction of an optical film in an extending | stretching part. The plurality of guide rollers are arranged in parallel to and around the axis. The endless belt is arranged to be stretched around a plurality of guide rollers. The material of the endless belt is preferably a synthetic resin, particularly polyurethane, but a steel belt can also be used.

  The end fixing member is rotatably supported on the shaft, is configured to be capable of attaching the end of the endless belt, and is configured to rotate about the shaft as the endless belt moves. The end fixing member prevents the endless belt from meandering due to the thrust force. Although it is preferable to fix both ends in the width direction of the endless belt by the end fixing members, the present invention is not limited to fixing both ends in the width direction of the endless belt by the end fixing members. If at least one end in the width direction of the endless belt is fixed by the end fixing member, meandering of the endless belt can be suppressed.

  In this configuration, the pressure rollers are not brought into pressure contact with each other as in the nip roll method, but the endless belt is brought into pressure contact with the pressure roller. Since the endless belt can easily adjust the holding angle of the pressure contact surface with the pressure roller by changing the position of a plurality of guide rollers that stretch the endless belt, the area of the pressure contact surface that presses the optical film is greatly expanded. It becomes possible. For this reason, even if the area of the pressure contact surface may slightly vary, the ratio of the change in the total area of the pressure contact surface can be kept low. As a result, the influence due to the area variation of the pressure contact surface is suppressed to a low level, and the stability when holding the optical film is hardly impaired.

  The optical film pressurizing apparatus according to the present invention further includes a roller support member that is provided on the shaft and supports the plurality of guide rollers so that the position of each guide roller can be adjusted in the direction of contact with the shaft. preferable. By making each guide roller approach or separate from the shaft, it becomes possible to adjust the holding angle of the pressure contact surface of the endless belt with the pressure roller and the tension of the endless belt. The pressure contact force with the pressure roller can be adjusted.

  According to this invention, it becomes possible to stably hold the optical film to be stretched.

  FIG. 1 shows an example of a stretching system to which the optical film pressurizing apparatus of the present invention is applied. The stretching system 10 includes a cleaning unit 12, a swelling unit 14, a dyeing unit 16, a stretching unit 18, a water washing unit 20, and a drying unit 22. Since a known configuration can be applied to portions other than the stretching portion 18 in the stretching system 10, the description thereof is omitted here.

  In this embodiment, a polarizing film made of polyvinyl alcohol (PVA) is used as the optical film 11. In the stretching system 10, the optical film 11 passes through the cleaning unit 12, the swelling unit 14, the dyeing unit 16, the stretching unit 18, the water washing unit 20, and the drying unit 22 in this order, and then the triacetyl cellulose (TAC) film 110 and the like. The protective film is affixed and collected. This invention has a feature in the holding method of the optical film 11 in the extending portion 18, and the feature will be specifically described below.

  FIG. 2 is a diagram showing an outline of the extending portion 18. An optical film pressurizing device 40 is applied to the stretching unit 18. As shown in FIG. 2, the optical film pressing device 40 is provided so as to replace the upper pressure roller that is in pressure contact with the lower pressure rollers 183, 185, and 187. The endless belt 38 of the optical film pressure device 40 is disposed so as to be in pressure contact with the pressure roller 185 via the optical film 11. When the endless belt 38 and the pressure roller 185 are in pressure contact, the optical film 11 to be stretched is held between the endless belt 38 and the pressure roller 185 with sufficient strength. The width of the endless belt 38 is set larger than the length of the pressure roller 185 in the axial direction. The endless belt 38 is provided with a contact portion to be in contact with the pressure roller 185 at the center in the width direction, and non-contact portions that are not in contact with the pressure roller 185 are disposed on both sides of the contact portion in the width direction. Configured to be.

  The configuration of the optical film pressurizing device 40 will be described with reference to FIGS. As shown in FIGS. 3A and 3B, the optical film pressurizing device 40 is attached to the bathtub 32 of the extending portion 18. Specifically, the optical film pressurizing device 40 includes a unit support portion 51 configured to be attachable to the bathtub 32 and a belt unit 52 supported by the unit support portion 51. The unit support portion 51 supports the pressure roll 185 that is housed in the bathtub 32 at both ends.

  The belt unit 52 includes an endless belt 38 made of synthetic resin, and a plurality of guide rollers 43 to 50 (see FIG. 2) that stretch the endless belt 38. The guide rollers 43 to 50 are arranged at equiangular intervals around the central axis 80. Considering the load applied to the endless belt 38, the guide rollers 43 to 50 are preferably arranged at equiangular intervals around the central shaft 80, but the guide rollers 43 to 50 are arranged at equiangular intervals around the central shaft 80. Arrangement is not an essential requirement, and it is also possible to arrange the guide rollers 43 to 50 at an arbitrary interval.

  Here, a drive motor 190 (see FIG. 4) as a drive source is provided on the pressure roller 185 side, and the endless belt 38 is configured to rotate with the rotation of the pressure roller 185. The reason for this is to simplify the configuration of the optical film pressurizing device 40 by not providing a drive source on the optical film pressurizing device 40 side. However, the endless belt 38 may be rotationally driven by providing a drive source on the optical film pressurizing device 40 side. In this embodiment, a synthetic resin (for example, polyurethane) is used for the endless belt 38, but a metal (for example, stainless steel) can be used instead of the synthetic resin.

  As shown in FIGS. 4 and 5, the belt unit 52 further includes an end fixing member 70 and a belt tension adjusting mechanism 53. The end fixing member 70 is rotatably supported on the central shaft 80 via a ball bearing, and is configured to be capable of attaching an end portion of the endless belt 38 and to move the central shaft 80 along with the movement of the endless belt 38. Configured to rotate around the center. In this embodiment, a plurality of holes are formed at both ends of the endless belt 38, and the endless belt 38 is constrained to the end fixing member 70 by the housing 71 and the bolt 72. However, the method of restraining both ends of the endless belt 38 is not limited to this. Here, the end fixing member 70 has a disk shape, but the shape of the end fixing member 70 is not limited to this. The end fixing member 70 is configured to restrict movement of the endless belt 38 in the width direction by restraining the outer periphery of both ends of the endless belt 38. Since the end fixing member 70 fixes the position of the end portion of the endless belt 38, the thrust force is forcibly restrained, so that the endless belt 38 does not meander. As a result, there is no need to provide a belt meandering correction device. Further, since no meandering occurs in the endless belt 38, no force acts in the width direction on the optical film 11 to be stretched, and the tension in the width direction of the optical film 11 can be stabilized.

  The housing 71 has a plurality of holes on the side surface. The reason is to adjust the belt tension adjusting mechanisms 53 to 60 installed inside the endless belt 38. Moreover, it is for avoiding the bad influence by sealing air by not sealing the inside of the optical film pressurization apparatus 40. FIG. However, the shape of the housing 71 is not limited to this, and the inside of the optical film pressurizing device 40 may be a sealed structure.

  As shown in FIG. 5B, the belt tension adjusting mechanism 53 is obtained by replacing the same mechanisms 54 to 60 with both end bearings 61 of the plurality of guide rollers 43 to 50 arranged radially as shown in FIG. Are provided in each case 62. Among them, the belt tension adjusting mechanisms 59 and 60 can also serve as a film holding angle adjusting mechanism.

  The belt tension adjusting mechanisms 53 to 60 support the guide rollers 43 to 50 so that the positions of the guide rollers 43 to 50 can be adjusted radially with the center axis 80 as a center. In this embodiment, a total of eight guide rollers 43 to 50 are supported at equal angular intervals around the central axis 80, but the number of guide rollers supported is not limited to this. For example, six guide rollers may be arranged at equiangular intervals, or twelve guide rollers may be arranged at equiangular intervals. The belt tension adjusting mechanisms 53 to 60 need not use all the tension adjusting mechanisms, and may adjust the tension of the endless belt 38 by using any number and arrangement of belt tension adjusting mechanisms. As shown in FIG. 5A, the tension adjustment mechanism 53 includes a jack 63 that can be rotated, and displaces the guide roller 43 according to the rotation of the jack 63.

  The belt tension adjusting mechanisms 59 and 60 having a film holding angle adjusting function support the guide rollers 49 and 50 so that their positions can be adjusted radially about the central axis 80. In this embodiment, the guide rollers 49 and 50 are supported so as to be radially displaceable about the central axis 80, but the displacement form of the guide rollers 49 and 50 is not limited to this.

  Further, when the endless belt 38 needs to be replaced due to deterioration, it is only necessary to remove the belt unit 52 and replace it with the belt unit 52 prepared in advance. It can be suppressed.

  6 (A) to 6 (D), the operation of the belt tension adjusting mechanisms 59 and 60 having the tension adjusting mechanisms 53 to 58 and the film holding angle adjusting function will be described. In the state of FIG. 5A, the belt tension adjusting mechanisms 59, 60 displace the guide rollers 49, 50 toward the center of the central shaft 80, so that as shown in FIG. 6B and FIG. 6D. In addition, the holding angle 400 of the pressure contact surface with the pressure roller 185 in the endless belt 38 can be reduced. On the other hand, in the state of FIG. 6 (A), the film holding angle adjusting mechanisms 59, 60 displace the guide rollers 49, 50 in the radial direction around the central axis 80, as shown in FIG. 6 (C). In addition, the holding angle 400 of the pressure contact surface with the pressure roller 183 in the endless belt 38 can be increased.

  Further, in the state of FIG. 6A, the tension adjusting mechanisms 53 to 60 displace the guide rollers 43 to 50 toward the center of the central shaft 80, whereby the tension of the endless belt 38 can be relaxed. In order to increase the tension of the endless belt 38, the tension adjusting mechanisms 53 to 60 may displace the guide rollers 43 to 50 in the radial direction around the central axis 80.

  According to the above configuration, when the optical film 11 is sandwiched between the endless belt 38 and the pressure roller 185, the area of the pressure contact surface that pressurizes the optical film 11 can be increased. In particular, as shown in FIG. 9B, the area of the pressure contact surface can be increased to about 20 times compared to when the optical film 11 is sandwiched between the rollers 184 and 185. For this reason, even if the area of the pressure contact surface may slightly vary, the ratio of the change in the total area of the pressure contact surface can be kept low. As a result, the influence due to the area variation of the pressure contact surface is suppressed to a low level, and the stability when holding the optical film 11 is not easily lost.

  Further, as shown in FIG. 7, the tension of the endless belt 38 is adjusted by the belt tension adjusting mechanisms 53 to 58, and the holding angle 400 is adjusted by the belt tension adjusting mechanisms 59 and 60 having the film holding angle adjusting function. The magnitude of the force N acting on the pressure roller 185 from the endless belt 38 can be adjusted. For this reason, according to the draw ratio of the optical film 11, it becomes possible to adjust the magnitude | size of the force holding the optical film 11 suitably.

  In the above-described embodiment, an example in which the guide rollers 49 and 50 are disposed at a position facing the pressure roller 185 is shown. However, the two guide rollers disposed at a position facing the pressure roller 185 are the guide rollers 49. And is not limited to 50. For example, by changing the arrangement angle of the belt unit 52, the other two guide rollers (for example, guide rollers 43 and 44) can be arranged at positions facing the pressure roller 185.

  FIG. 8 shows an outline of the stretching system 102 according to the second embodiment. In the stretching system 102, the optical film pressing device 40 is applied to the optical film position at a position different from the stretching system 10.

  FIG. 9 is a diagram illustrating an outline of the extending portion 18 according to the second embodiment. As shown in FIG. 9A, in the second embodiment, an optical film pressure device 40 is provided so as to be in pressure contact with the pressure roller 183. As described above, the attachment position of the optical film pressurizing device 40 with respect to the stretching portion 18 can be arranged at an arbitrary location of the stretching portion 18.

  In the above-described embodiment, an example in which the single optical film pressing device 40 is applied to the stretching system 10 or the stretching system 102 has been described. However, a plurality of optical film pressing devices 40 may be applied to the stretching system 10. It is. For example, it is possible to apply two optical film pressurizing devices 40 as shown in FIG. 9B, or to apply three optical film pressurizing devices 40 as shown in FIG. 9C. .

  In the above-described embodiment, the wet stretching method has been described. However, the present invention can also be applied to a stretching system that adopts a dry stretching method.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

It is a figure which shows the example of the extending | stretching system to which an optical film pressurization apparatus is applied. It is a figure which shows the outline of an extending | stretching part. It is a figure which shows the outline of an optical film pressurization apparatus. It is a figure which shows the outline of an optical film pressurization apparatus. It is a figure which shows the structure of a belt unit. It is a figure explaining the position adjustment of the guide roller in an optical film pressurization apparatus. It is a figure which shows the effect | action of a belt unit. It is a figure which shows the other example of an extending | stretching part. It is a figure which shows the other example of an extending | stretching part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 102-Stretching system 18-Stretching part 40-Optical film pressurizer 51-Unit support part 52-Belt unit 43-50-Guide roller 53-60-Belt tension adjustment mechanism

Claims (4)

An optical film pressurizing device configured to press-contact the pressurizing roller configured to contact an optical film to be stretched through the optical film,
A belt unit disposed so as to be in pressure contact with the pressure roller;
A unit support configured to support the belt unit;
With
The belt unit is
An axis disposed horizontally so as to be orthogonal to the traveling direction of the optical film in the stretching portion;
A plurality of guide rollers arranged in parallel to and around the axis;
An endless belt arranged to be stretched between the plurality of guide rollers;
An end fixing member that is rotatably supported by the shaft, is configured to be capable of attaching an end of the endless belt, and is configured to rotate around the shaft as the endless belt moves. ,
An optical film pressurizing device.   2. The optical film additive according to claim 1, further comprising a roller support member provided on the shaft and supporting the plurality of guide rollers for each guide roller so that the position of the plurality of guide rollers can be adjusted in a direction away from the shaft. Pressure device.   The endless belt has a contact portion to be in contact with the pressure roller at a central portion in the width direction parallel to the shaft, and a non-contact portion that does not contact the pressure roller is the contact portion in the width direction. The optical film pressurizing apparatus according to claim 1, wherein the optical film pressing apparatus is configured to be disposed on both sides of the optical film. The end fixing member has a disk shape;
The optical film pressurizing apparatus according to claim 1, wherein the plurality of guide rollers are arranged at equiangular intervals around the shaft.

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