JP2014164001A - Production method for optical film and system for controlling traveling of optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cutting a long patterned optical film in a direction parallel to the longitudinal direction, and to provide a system for controlling traveling of an optical film.SOLUTION: A production method of an optical film is provided, which includes: a position detection step where a traveling position in the width direction of an optical film 1 that travels in the longitudinal direction is detected by a position detecting unit 20; a position correction step where the traveling position in the width direction of the optical film is corrected in accordance with the detection results in the position detection step so as to maintain the traveling position to be constant in the width direction; and a cutting step where the patterned optical film is cut at a predetermined position in a direction parallel to the longitudinal direction. In the position detection step, a boundary line 105 between a first region 101 and a second region 102 of the optical film is optically detected by using a light-dark pattern formed by beams in different polarization states from each other.

Description

  The present invention relates to a method for producing an optical film. Specifically, the present invention relates to a method of cutting an optical film parallel to the longitudinal direction by controlling the running state of a long optical film. Furthermore, the present invention relates to an optical film traveling control system for controlling the traveling state of the optical film.

  In recent years, with the increase in the size of screens of televisions and information displays and the rapid spread of mobile devices such as smartphones and tablet computers, the demands for improving the image quality of image display devices have been diversified and advanced. Various optical films are used in the image display device. For example, in a liquid crystal display device, a polarizing plate is an essential component from the principle of image display, and in addition, optical films such as a retardation film and a viewing angle widening film are used. Further, in a stereoscopic video apparatus or the like, a pattern optical film is used in which right-eye video formation regions and left-eye video formation regions having different polarization characteristics are alternately formed in a stripe shape.

  In the production of an optical film, generally, predetermined optical properties are imparted by coating, stretching, bonding and the like while a long film (web) is conveyed in the longitudinal direction. Thereafter, the optical film formed in a long shape is cut at a predetermined position to form a sheet having a product size that matches the screen size of the video display device.

  Many of these optical films exhibit their functions based on the anisotropy of optical properties. Therefore, in order to improve the image quality of the image display device, the optical axis direction of the optical film is required to be constant. In order to make the optical axis direction of the optical film uniform, in addition to the axial direction in each process such as coating, stretching, and bonding being constant, processing accuracy when cutting the film (position of cutting) And the accuracy of the angle is important. Further, in the case of a patterned optical film or the like, since it is necessary to match the pitch of the pixel of the display device and the pattern of the optical film, in addition to the constant axial direction, it is necessary to cut at a predetermined position.

  However, when a long film is conveyed while being unwound from a wound body, meandering due to uneven thickness of the film, non-uniform tension, etc. occurs, and the position and angle of the cutting process are displaced. In general, an edge position controller (EPC: registered trademark) is used in order to prevent such processing deviation due to meandering. EPC is a system that detects film edges and controls film travel so that the position is always constant.

  The method of correcting the meandering by detecting the edge of the film can control and correct the film running position with an accuracy of about several millimeters. However, when the curl or the like is deformed at the end of the film, the position of the edge slightly changes depending on the state of curling or the like, so that it is difficult to control the position with an accuracy of μm level. On the other hand, in order to meet the demand for higher image quality and higher definition of the displayed image, it is required to control the film conveyance with higher accuracy and to make the optical axis direction and the cutting position of the optical film constant. It has become.

  In view of such a problem, it has been proposed to detect the running state of the film and perform position correction by detecting marks attached at predetermined intervals in the longitudinal direction (running direction) of the long film. . For example, in Patent Document 1, a mark is formed at a reference position upstream of the film conveyance path, and the mark is detected downstream to calculate the film conveyance state (meandering angle θ), and based on the calculation result. A method for detecting a running state is disclosed.

JP 2012-230380 A

  If the film running position is detected and corrected by detecting a mark as in Patent Document 1, accurate position control can be performed even if a curl or the like is deformed at the end of the film. However, in order to accurately calculate the meander angle θ by detecting the mark attached upstream of the conveyance path downstream by the method disclosed in Patent Document 1, the span from the formation of the mark to the detection is lengthened. There is a need to. For this reason, it takes time until an abnormality in the running state (for example, meander angle) is fed back upstream and position correction is performed, and the product during that time becomes defective, so there is a tendency for yield to decrease. On the other hand, if the span from the formation of the mark to the detection is shortened, the calculation accuracy of the meander angle θ decreases, so that it is difficult to control the film travel position so that the cutting is performed at the desired position. is there.

  Moreover, in manufacture of an optical film, several processes, such as application | coating, extending | stretching, bonding, and a cutting | disconnection, are performed sequentially. When passing through such a plurality of steps, in each step, if it is attempted to correct the running state by detecting the running state of the film by the method of detecting the mark, the mark attached in the previous step is changed to the subsequent step. There may also be a problem such as a false detection that it is detected in the above. Furthermore, the method of detecting the mark attached upstream is likely to complicate the apparatus and control mechanism for forming the mark.

  In view of the above problems, the present invention detects a traveling position of a film easily and with high accuracy when a long optical film is cut at a predetermined position, and corrects the displacement of the traveling position, thereby correcting the optical film. The goal is to produce high yields.

  This invention is a manufacturing method of an optical film, Comprising: It has the process (cutting process) of cut | disconnecting an elongate optical film in the direction parallel to a longitudinal direction. The optical film has a first region and a second region extending in the longitudinal direction, and the first region and the second region have optical characteristics in which polarization states are different from each other.

  The manufacturing method of the optical film of this invention has a position detection process, a position correction process, and a cutting process. The position detection step is a step in which the position detection unit detects the traveling position in the width direction of the optical film traveling in the longitudinal direction. In the position detection unit, the boundary line between the first region and the second region of the optical film is optically detected by light and darkness formed based on different polarized light. The position correction step is a step in which the traveling position in the width direction is corrected so that the traveling position of the optical film is kept constant in the width direction according to the detection result in the position detection step. The cutting step is a step in which the optical film is cut at a predetermined position in a direction parallel to the longitudinal direction.

  Furthermore, the present invention relates to an optical film traveling control system for traveling a long optical film in parallel with the longitudinal direction. The optical film travel control system of the present invention includes a position detection unit and a position correction mechanism. The position detection unit detects a traveling position in the width direction of the optical film traveling in the longitudinal direction. In the position detection unit, the pattern boundary is detected based on light and darkness formed based on different polarizations. The position correction mechanism corrects the traveling position in the width direction so that the traveling position of the optical film is kept constant in the width direction according to the detection result of the position detection unit.

  In one embodiment, the optical film used in the present invention has optical characteristics in which the first region and the second region are orthogonal to each other. In this case, the position detection unit can detect the boundary between the first region and the second region as a boundary between black and white (a portion where the light reaches the light receiving element and a portion where the light hardly reaches). Therefore, when detecting the position of the boundary, the contrast between the first region and the second region is increased, and the detection accuracy is increased.

  According to the present invention, the boundary between the first region and the second region of the optical film is detected via the polarizing means by utilizing the optical characteristics of the polarization states different from each other. Is done. And control (correction | amendment) of the running position of an optical film is performed so that the position of this boundary line may become fixed. Therefore, even when the end of the optical film is deformed such as curl, the traveling position can be corrected so that the traveling position of the optical film is constant. As described above, the travel position is corrected based on the boundary between the first area and the second area having different optical characteristics, so that the boundary line serving as the travel position detection reference and the cutting position in the cutting process are obtained. The relative positional relationship with is kept constant. Therefore, in the cutting step, the optical film can be cut at a predetermined position in a direction parallel to the extending direction of the boundary, that is, in parallel with the longitudinal direction.

  In addition, according to the present invention, since it is not necessary to add a mark or the like for position detection, the configuration and control of the transport device can be simplified. Furthermore, since the position correction mechanism can be arranged in the vicinity of the upstream position of the conveyance path of the position detection unit, deviations in travel position and travel angle such as meandering are fed back upstream in a short time. With such a configuration, the occurrence of defective products whose cutting position and cutting direction deviate from the intended positions is suppressed, and the yield of the optical film can be improved.

It is a figure which represents typically the structural example of an optical film. (A) is a top view, (B) is sectional drawing in the width direction. It is sectional drawing showing the outline | summary of the structure of the manufacturing process of an optical film, and an optical film travel control system. It is a perspective view of the principal part of FIG. It is a conceptual diagram for demonstrating the structural example of a position detection part, and the principle of position detection. It is typical sectional drawing for demonstrating a mode that correction | amendment of the running position of a film is performed by detecting a pattern boundary. It is typical sectional drawing for demonstrating a mode that correction | amendment of the running position of a film is performed by detecting the edge of a film. It is a top view which represents typically an example of a mode that an optical film is cut-processed. It is a top view which represents typically the mode of a cutting line in case the running position of a pattern optical film is correct | amended. It is sectional drawing which represents typically the structural example of an optical film. It is a conceptual diagram for demonstrating the structural example of a position detection part, and the principle of position detection. It is a conceptual diagram for demonstrating the structural example of a position detection part, and the principle of position detection. It is a figure which represents typically the structural example of a pattern optical film. (A) is a top view, (B) is sectional drawing in the width direction. It is sectional drawing which represents typically the structural example of a pattern optical film. It is a top view which represents typically the structural example of a pattern optical film.

  First, the optical film used in the present invention will be described. FIG. 1A is a plan view schematically illustrating a configuration example of an optical film, and FIG. 1B is a cross-sectional view thereof. The optical film 1 has a first region 101 and a second region 102. The first region 101 and the second region 102 extend in the longitudinal direction (MD direction). Therefore, the boundary line 105 between the first region 101 and the second region 102 also extends in the longitudinal direction. The long optical film 1 is finally cut into a single-piece optical film 1a to 1h having a predetermined shape through a cutting process to become a product.

  The first region 101 and the second region 102 of the optical film 1 have optical characteristics with different polarization states. “The polarization states of the first region and the second region are different from each other” means that the optical film is an arbitrary film between two polarizing plates (polarizer and analyzer) arranged in crossed Nicols or parallel Nicols. When arranged at an angle, it means that the transmittance of the first region and the second region are different. For example, when the first region and the second region have different polarization axis directions, or when the first region and the second region have different birefringence characteristics (retardation or optical axis direction), both The polarization states of are different from each other.

  The optical film 1 has a first polarizing region 131 and a second polarizing region 132 on a base film 110 made of an optical isotropic film or an optical anisotropic film. Examples of the optically anisotropic film include a retardation plate and a polarizing plate. Each of the first polarizing region 131 and the second polarizing region 132 is formed in a strip shape extending in the longitudinal direction, and both are adjacent along the boundary line 105. Such an optical film is manufactured by forming the polarizing regions 131 and 132 thereon by coating or the like while conveying the long base film 110 in the longitudinal direction. The first polarizing region 131 and the second polarizing region 132 are configured so that, for example, the absorption axis directions are orthogonal to each other. In the configuration shown in FIG. 1, the first polarizing region 131 has an absorption axis 131a in the longitudinal direction, and the second polarizing region 132 has an absorption axis 132a in the width direction. Although the width | variety in particular of the 1st polarizing region 131 and the 2nd polarizing region 132 is not restrict | limited, For example, it is about 1 micrometer-10 cm.

  The optical film manufactured continuously in the longitudinal direction is finally cut into sheet bodies 1a to 1h according to the screen size of the video display device to become a product. The present invention relates to a method of cutting an optical film formed in such a long shape at a predetermined position in a direction parallel to the longitudinal direction, and an optical film traveling control system used for the cutting. Note that, as in the case of punching and cutting of a film, cutting in a direction parallel to the longitudinal direction and cutting in the direction orthogonal to the longitudinal direction (width direction) may be performed at that time.

  FIG. 2 is a cross-sectional view showing the outline of the configuration of the optical film manufacturing process of the present invention and the optical film traveling control system used in the manufacturing process. FIG. 3 is a perspective view of a main part in FIG. The optical film travel control system 500 includes a position detection unit 20 and a position correction mechanism 30. The position detection unit 20 detects a traveling position in the width direction of the optical film 1 traveling in the MD direction. The position correction mechanism 30 corrects the travel position in the width direction so that the travel position of the optical film is kept constant according to the travel position detection result in the position detection unit 20. The position correction mechanism 30 includes, for example, a guide roller 32 including an operation unit 31 such as an actuator, and the position detection unit 20 and the operation unit 31 are linked via an appropriate control unit 40.

  FIG. 4 is a conceptual diagram for explaining a configuration example of the position detection unit 20 and the principle of position detection using polarized light. In the position detection unit 20, a light source 21 and a light receiving unit 29 are provided on the normal line of the film running surface S so as to face the film running surface S. In FIG. 4, a polarizing plate 23 is provided between the light source 21 and the film running surface. The polarizing plate 23 has an absorption axis in a direction orthogonal to the traveling direction of the optical film, that is, in the width direction.

  The absorption axis direction of the polarizing plate 23 and the absorption axis direction of the polarizing region 131 on the first region of the optical film are orthogonal to each other. The light emitted from the light source 21 (for example, natural light) is absorbed by the polarizing plate 23 into light that vibrates in the normal direction of the paper surface, and is emitted to the optical film 1 side as linearly polarized light that vibrates in the horizontal direction of the paper surface. Since the absorption axis direction of the polarizing plate 23 and the absorption axis direction 131a of the polarizing region 131 are orthogonal, the linearly polarized light emitted from the polarizing plate 23 is absorbed by the polarizing region 131 on the first region. On the other hand, the absorption axis direction of the polarizing plate 23 and the absorption axis direction 132a of the polarization region 132 on the second region of the optical film are parallel. Therefore, the linearly polarized light emitted from the light source 21 and transmitted through the polarizing plate 23 is not absorbed by the polarization region 132 on the second region and is emitted to the light receiving unit 29 side.

  The light receiving unit 29 is an image sensor such as a photodiode array or a camera, for example, and includes a plurality of light receiving elements in the width direction. In the form shown in FIG. 4, since light is absorbed by the polarizing layer in the first region 101, the light receiving element corresponding to the position of the first region 101 (the right half of the light receiving unit 29 in FIG. 4) has a light source. The light from the light source 21 does not reach (or only a small amount of light arrives) and only from the light source 21 corresponding to the position of the second region 102 (the left half of the light receiving unit 29 in FIG. 4). The light reaches. Therefore, the position of the boundary 105 between the first region 101 and the second region 102 of the optical film 1 is a position where the amount of light reaching each light receiving element in the light receiving unit exceeds a predetermined threshold, that is, as a light / dark boundary, It is detected by the light receiving unit. The light / dark boundary, that is, the boundary between the first region and the second region can be detected by image analysis or the like based on the amount of light received by each light receiving element.

  In FIG. 4, an example in which the polarizing plate 23 is provided between the light source 21 and the film traveling surface S is illustrated, but the polarizing plate may be disposed on the normal line of the optical film traveling surface S. For example, in FIG. 4, instead of the polarizing plate 23 between the light source 21 and the film running surface S, a polarizing plate 25 may be provided between the light receiving unit 29 and the film running surface S. In this case, the light incident on the optical film 1 from the light source 21 is emitted to the polarizing plate 25 side as linearly polarized light orthogonal to each other in the first region 101 and the second region 102. Since the light from one region is absorbed by the linearly polarizing plate 25 and the light from the other region is transmitted through the linearly polarizing plate 25, the position of the boundary line 105 is based on the light / dark boundary as in the previous case. Detected.

  An optical element such as a lens or a mirror may be arranged on the optical path from the light source 21 to the light receiving unit 29. When a mirror or the like is arranged, “the light source, (circular) polarizing plate, light receiving part, etc. are arranged on the normal line of the optical film running surface” means that the light path from the light source to the light receiving part and the film running The case where the surfaces S are orthogonal and an optical element such as a (circular) polarizing plate is disposed on the optical path is included.

  In the optical film travel control system 500, the position detection unit 20 is disposed in the vicinity of the guide roller 32 of the position correction mechanism 30. The position detection result by the position detection unit 20 is output to the control unit 40. In the control unit 40, the optical film travel reference position V is set in advance, and whether the detection result (the position of the boundary line 105 of the optical film) in the position detection unit 20 matches the reference position V. Is determined. When the traveling position of the film does not coincide with the traveling reference position, it is determined to which side the traveling position is shifted with respect to the reference position, and the distance between the traveling position of the optical film 1 and the reference position is calculated. The Based on the calculation result, the control unit 40 transmits a command to the position correction mechanism 30 to correct the deviation of the boundary 105 traveling position of the optical film 1 from the reference position V, and the operation control (position correction) is performed. Done. The operation control may be performed only when a predetermined threshold value is input in advance to the control unit 40 and the distance between the travel position of the boundary line 105 and the reference position V is equal to or greater than the threshold value.

  The configuration of the position correction mechanism 30 is not particularly limited as long as the traveling position of the film can be changed (controlled) in the width direction. The position correction mechanism 30 includes, for example, a guide roller 32 provided with an operation unit 31 such as an actuator, and the operation unit 31 changes the posture (position, angle, etc.) of the guide roller 32 in accordance with a command from the control unit 40. Thus, the film running position is corrected.

FIG. 5 is a cross-sectional view showing a state in which the film traveling position is corrected by the position detecting unit 20 detecting the boundary 105. The position detection unit 20 detects the position of the boundary 105 and the position correction mechanism 30 corrects the traveling position so that the position coincides with the reference position V. Therefore, Figure 5 distance 5 distance from the edge of the optical film 1 to the cutting line forming position C1 is W ₁ (A), and from the edge of the optical film 1 to the cutting line forming position C1 is W ₂ ( In any case of B), the travel position is corrected by the position correction mechanism 30 so that the boundary 105 returns to the reference position V. Therefore, if the boundary line 105 is formed in parallel with the longitudinal direction, control is performed so that the optical film travels in parallel with the longitudinal direction even when the end of the optical film is deformed such as curl. Thus, the position in the width direction of the cutting line forming position C1 in the optical film traveling control system can be kept constant.

FIG. 6 illustrates a case where the position detection unit 220 detects the position with reference to the edge position E of the film, thereby correcting the traveling position of the film. When the distance from the edge E of the optical film 1 to the cutting line forming position C201 is changed from W ₁ (FIG. 6A) to W ₂ (FIG. 6B), the cutting line is formed in the optical film traveling control system. The position in the width direction of the position C201 also changes. Therefore, when deformation such as curl occurs at the end of the film, traveling control is performed such that the cutting line formation (planned) position C201 is different from the intended reference position, and in the subsequent cutting process A cutting line is formed at a position different from the intended position.

  In the present invention, as shown in FIG. 5, by utilizing the fact that the first region and the second region of the optical film have different polarization characteristics, the boundary 105 between the two is located at a position detection unit including a polarizing element. Control is performed so that the position is constant. Therefore, even when the end portion of the optical film is deformed, it is possible to control travel so that the cutting line formation (planned) position is constant. 4 and 5 show an example in which the first region 101 and the second region 102 are provided in the vicinity of the edge of the optical film 1, the first region 101 is provided in the vicinity of the center in the width direction of the optical film. Even in the case of having the region, the second region, and the boundary line thereof, the film traveling position can be detected and corrected by the same principle.

  The above has described an example in which the position detection unit 20 detects the position in the width direction of the boundary 105 between the first region 101 and the second region 102 of the optical film 1. In addition to the position of 105, the traveling angle of the boundary line and the like may be detected. For example, when a planar light source 21 and a light receiving unit 29 (for example, a camera) in which a plurality of light receiving elements are arranged in a planar shape are used, a boundary between light and dark is detected in two dimensions. Can be obtained. In this case, the position correction mechanism 30 corrects the travel position so that the position of the boundary line 105 coincides with the reference position V, and the film travel state is controlled so that the travel direction of the boundary line is constant. May be. For example, if two or more guide rollers (for example, the guide roller 55 in addition to the guide roller 32) are configured to be operable based on a command from the control unit 40, the traveling angle of the film can be controlled.

  Note that the optical film travel control system can correct the position if the position detection unit 20 is configured to detect the boundary 105 between the first region and the second region based on the brightness formed based on the polarization. The configurations of the mechanism 30 and the control unit 40 are not particularly limited. As the position correction mechanism and the control unit, for example, a configuration similar to the position correction mechanism and control unit used in a system (edge position controller) that detects the edge of the film and corrects meandering can be appropriately employed.

  In the method for producing an optical film of the present invention, as shown in FIG. 2, the wound body 2 of the long optical film 1 is set in the feeding portion 50. The optical film 1 is conveyed from the feeding unit 50 to the guide roller 32 of the position correction mechanism 30 via the conveying rollers 51, 52, 53, and the position detection unit 20 uses the boundary between the first region and the second region. The position is detected.

  In the position detection step, as described above, the first region 101 and the second region 102 utilize the fact that the polarization characteristics of the optical film are different at the boundary 105, and thus the position detection unit 20 including a polarizing element. Thus, the running state is detected. In the position correction step, it is determined whether or not the detected position of the boundary line 105 matches a preset driving reference position V. If the two do not match (or if the distance between the two is equal to or greater than the threshold), the travel position is corrected (operation control) by the position correction mechanism 30 so that the position of the boundary 105 matches the travel reference position V. .

  Thereafter, the optical film 1 is conveyed to the cutting processing unit 60 through the guide roller 55. Since the travel position in the width direction is corrected upstream of the transport path, the optical film 1 has a boundary 105 between the first area and the second area at a predetermined position in the width direction on the guide roller 55. After passing, it is introduced into the cutting unit 60 while maintaining its running state. Accordingly, the cutting line formation (planned) position C1 is also introduced into the cutting processing unit 60 while maintaining its traveling state after passing through a predetermined position in the width direction on the guide roller 55.

  In the cutting step, the optical processing unit 60 cuts the optical film 1 in a direction parallel to the extending direction of the boundary line 105. FIG. 7 is a plan view schematically showing how the optical film 1 is cut by the cutting processing unit 60. The optical film 1 in which the position detection in the width direction is performed upstream and the traveling position is corrected is cut along, for example, cutting lines C11 to C14 having a constant interval to form a plurality of cutting pieces 1A, 1B, and 1C. The The blank portion 1X at the end in the width direction of the optical film 1 is removed by cutting by the cutting processing unit 60.

  The width of each of the cut pieces 1A, 1B, 1C can be arbitrarily set according to the use of the optical film. For example, when the optical film is used in an image display device such as a liquid crystal display device, the cutting width of each cut piece is set in accordance with the screen size (screen width or screen height). In FIG. 7, the first region 101 and the second region 102 are included in the blank portion 1X and are removed by cutting. However, depending on the product specifications, the first region 101 The second region may be included in the product portion (cut pieces 1A to 1C).

FIG. 8 is a plan view schematically showing the state of the cutting line when the traveling position of the optical film 1 is corrected. When the distances W ₁ and W ₂ from the edge of the optical film 1 to the cutting line formation (planned) position C1 are not constant in the film longitudinal direction (MD) due to meandering at the time of optical film formation such as coating However, according to the present invention, the traveling position is corrected so that the position of the boundary 105 is constant. Therefore, the cutting lines C11 and C21 are formed on the cutting line forming (planned) position C1 regardless of the change in the distance from the edge to the cutting line forming (planned) position (FIG. 8A). In addition, the position detection unit 20 is disposed in the vicinity of the position correction mechanism 30 to shorten the feedback time of the position detection result, or by detecting the traveling angle of the boundary 105 in the position detecting unit, the traveling direction (traveling angle). It is possible to carry out travel control so that is constant. Therefore, even when the optical axis direction of the optical film is not parallel to the MD direction, if the optical axis direction of the optical film and the boundary line 105 are parallel, the traveling direction of the film and the optical axis direction are parallel. In addition, the travel position (travel direction) can be corrected, and the cut lines C11 and C31 are formed on the cut line formation (planned) position C1.

  7 and 8 show an example in which cutting is performed so that the cutting line C is formed inside the width direction from the boundary 105, the cutting line is parallel to the boundary line 105, that is, MD. As long as it extends in the direction, the position may be outside of the boundary line 105 in the width direction or on the boundary line 105.

  The optical film cut pieces 1A, 1B, and 1C cut to a predetermined width are then further cut in the width direction to form a single-wafer optical film of a predetermined size. In addition to cutting in a direction parallel to the extending direction (longitudinal direction) of the boundary line 105, the cutting unit 60 also cuts in a direction orthogonal to the extending direction of the boundary 105, that is, in the width direction. You may do it. For example, when the cutting unit 60 includes punching means such as a Thomson blade, a sheet-like optical film can be obtained by punching a long optical film into a predetermined size.

  As described above, the manufacturing process of the present invention centering on the example of the optical film having the first polarizing region 131 and the second polarizing region 132 whose absorption axis directions are orthogonal to each other in each of the first region 101 and the second region 102. The configuration of the optical film travel control system has been described. In addition, as long as a 1st area | region and a 2nd area | region have an optical characteristic from which a polarization state mutually differs, both polarization states will not necessarily be orthogonal to an optical film. If the polarization states of the first region and the second region are different, the position detection unit can detect the position of the boundary based on the difference between light and dark (difference in transmittance) at the boundary between the two, As in the case where the polarization states of the two are orthogonal, the running state of the film can be controlled so that the position of the boundary line 105 is constant.

  FIGS. 9A to 9E are cross-sectional views schematically showing other examples of the optical film that can be used in the present invention. In the optical film 11 of FIG. 9A, the first polarizing region 131 is formed on the first region 101 of the base film, and the polarizing region is not formed on the second region 102. Even if it is such a form, if the position detection part 20 has the polarizing plate 23 (or 25) arrange | positioned so that the absorption axis direction may orthogonally cross with the 1st polarization area 131, the 2nd Since the light from the light source 21 is detected only by the light receiving element corresponding to the region 102, the position of the boundary line 105 can be detected.

  In the optical film 12 of FIG. 9B, a first retardation region 121 is formed on the first region 101 of the base film, and a polarizing layer or a retardation layer is formed on the second region 102. Not formed. In such a form, as shown in FIG. 10, the position detection unit 20 includes polarizing plates 23 and 25 between the light source 21 and the film running surface S and between the light receiving unit 29 and the film running surface, respectively. , The boundary 105 between the first region 101 and the second region 102 can be optically detected by light and darkness formed based on mutually different polarized light. For example, the angle formed by the absorption axis direction of the polarizing plate 23 and the slow axis direction of the first retardation region 121 is 45 °, and the first retardation layer has a retardation of ½ of the wavelength λ. The linearly polarized light emitted from the polarizing plate 23 and incident on the optical film 1 has its vibration direction rotated by 90 ° by the retardation layer. Therefore, as schematically shown in FIG. 10, the light emitted from the first region and the light emitted from the second region are linearly polarized light orthogonal to each other, and the light from one region is reflected by the linearly polarizing plate 25. Since the light from the other region is absorbed and passes through the linearly polarizing plate 25, the position of the boundary line 105 is detected based on the light / dark boundary.

  Further, as shown in FIG. 9C, the first retardation layer region was formed on the first region 101 of the base film, and the second retardation region 122 was formed on the second region 102. The optical film 13 can also be used. Also in such a form, as shown in FIG. 10, the position detection unit 20 includes polarizing plates 23 and 25 between the light source 21 and the film running surface S and between the light receiving unit 29 and the film running surface, respectively. , The boundary 105 between the first region 101 and the second region 102 can be optically detected by light and darkness formed based on mutually different polarized light.

  When the optical film 13 having the retardation regions 121 and 122 having optical characteristics having different polarization states is used in the first region and the second region, the position detection includes the circularly polarizing plate 24 as shown in FIG. Position detection can also be performed by the unit 20.

  FIG. 11 is a conceptual diagram for explaining a configuration example of the position detection unit 20 including a circularly polarizing plate and the principle of position detection. In the position detection unit 20 shown in FIG. 11, a polarizing plate 23 is provided between the light source 21 and the film running surface S, and a quarter wavelength is provided between the light receiving unit 29 and the film running surface S. A circularly polarizing plate 24 in which a plate 27 and a polarizing plate 25 are laminated is provided.

  Light (for example, natural light) emitted from the light source 21 is absorbed by the polarizing plate 23 into light that vibrates in the normal direction of the paper surface, and is emitted to the optical film 13 side as linearly polarized light that vibrates in the horizontal direction of the paper surface. When both the first region 101 and the second region 102 of the optical film 13 have a retardation of ¼ wavelength and are configured such that the slow axis directions thereof are orthogonal to each other, the optical film The light emitted from the first region 101 to the circularly polarizing plate 24 side and the light emitted from the second region 102 to the circularly polarizing plate 24 side are circularly polarized light (right circularly polarized light and left circularly light). Polarized light).

  The circularly polarizing plate 24 is disposed on the optical film running surface S side of the linearly polarizing plate 25 so that the quarter wavelength plate 27 is located. The angle formed by the absorption axis direction of the linear polarizing plate 25 and the slow axis direction of the quarter-wave plate is set to 45 °. The linearly polarizing plate 25 and the quarter-wave plate 27 may be bonded and laminated, or both may be arranged so as to be separable.

  Since circularly polarized light orthogonal to each other is emitted from the first region 101 and the second region 102 of the optical film 13, one circularly polarized light (emitted light from the first region 101) is caused by the circularly polarizing plate 24. The other circularly polarized light (emitted light from the second region 102) that has been absorbed is transmitted through the circularly polarizing plate 24 and emitted to the light receiving unit 29 side.

  In FIG. 11, an example in which the circularly polarizing plate 24 is used as an analyzer provided between the light receiving unit 29 and the film running surface S is illustrated. However, the circularly polarizing plate 24 is on the normal line of the optical film running surface S. It suffices if they are arranged. For example, as a polarizer between the light source 21 and the film running surface S, a circularly polarizing plate in which a polarizing plate and a quarter wavelength plate are laminated may be provided. In this case, the light emitted from the light source 21 is converted into circularly polarized light by the circularly polarizing plate and reaches the optical film 1. The light emitted from the first region 101 to the light receiving unit side and the light emitted from the second region 102 to the light receiving unit side are linearly polarized light whose polarization directions are orthogonal to each other. Light from one region is absorbed by the linear polarizing plate on the light receiving unit side, and light from the other region is transmitted through the linear polarizing plate on the light receiving unit side. The position of the boundary line 105 is detected based on the light / dark boundary.

  Moreover, in the form which has a phase difference layer in a 1st area | region and / or a 2nd area | region like the optical films 12 and 13 of FIG.9 (B) and FIG.9 (C), retardation of retardation layer is shown. When the transmitted light is colored due to wavelength dispersion or the like, the boundary can be detected based not only on light and darkness (transmittance difference) but also on a color difference or the like.

  The present invention is limited to those in which a polarizing layer or a retardation layer is formed on a base film, as long as the first region and the second region of the optical film have optical properties with different polarization states. Not applicable to various optical films. For example, the present invention is applicable to a laminated optical film in which a second film is laminated on a part of the first film in the width direction.

  In FIG. 9D, a protective layer 150 as a second film is laminated at the center in the width direction of a base film 110 as a first film. A protective layer is not laminated on the end of the base film 110 in the width direction. As the protective layer 150, a stretched polyester film, a stretched polyolefin film, or the like is used. When a film having optical anisotropy, such as a stretched film, is used as the protective layer, the protective layer 150 has a retardation, and thus the first region 101 where the protective layer is not laminated, and the protective layer 150 The second region 102 in which is stacked has optical characteristics with different polarization states. Therefore, the position of the edge of the protective layer 150 can be detected by the detection unit 20 including the polarizing element with the boundary 105 as the boundary 105. Since the edge 105 of the protective layer 150, that is, the boundary 105 between the first region and the second region exists on the base film 110, deformation such as curling is suppressed as compared with the edge of the optical film 14. . Therefore, more accurate traveling control can be performed as compared with the case where traveling control is performed by detecting the edge of the optical film 14.

  Further, as shown in FIG. 9E, when the base film 115 is an optical anisotropic film such as a retardation film, an optical in which a protective layer 150 having a larger width than the base film 115 is laminated. A film 114 'can also be used. In this case, the first region 101 having only the protective layer 150 and not having the base film, and the second region 102 in which the protective layer 150 is laminated on the base film 115 are in a polarization state. Have different optical properties. Therefore, the position of the base film 115 can be detected by the detection unit 20 including the polarizing element with the edge 105 as the boundary 105.

  As described above, in the optical film traveling control system of the present invention, the optical film has different polarization characteristics with the boundary between the first region and the second region as a boundary. The traveling position of the boundary is detected by the provided position detection unit. Therefore, even if the curl or the like is deformed at the end of the film or the distance from the film edge to the cutting line forming position changes in the MD direction, the optical film in the travel control system Control is performed so that the relative position is constant.

  In the manufacturing method of the present invention, the optical film whose travel position is controlled (corrected) by the travel control system is used in the cutting process. Since control is performed so that the cutting line forming position travels at a predetermined position in the width direction, it is possible to perform cutting at a fixed relative position, and a defect that causes cutting at an undesired position or occurrence of shaft misalignment. Can be suppressed, and can contribute to the improvement of the yield of the optical film.

  Furthermore, according to the configuration of the present invention, even when deformation such as curl occurs at the end of the film, the traveling position of the film can be accurately detected without being affected by such deformation, and several μm to The film traveling position can be controlled and corrected with an accuracy of several tens of micrometers. Therefore, this invention is useful also for the cutting | disconnection of the optical film which has a micro pattern like the pattern optical film used for a three-dimensional image display apparatus. A pattern optical film used for a stereoscopic image display device or the like needs to match the pitch of the pixel of the display device and the pattern of the optical film, and is required to keep the cutting position constant with an accuracy of several μm to several tens of μm. .

  FIG. 12A is a schematic plan view illustrating a configuration example of a pattern retardation plate according to an embodiment of the patterned optical film. Both the first region 101 and the second region 102 of the pattern retardation plate 15 have a retardation of ¼ wavelength of visible light, and are configured such that the slow axis directions thereof are orthogonal to each other. Yes.

  FIG. 12B is a schematic cross-sectional view of the pattern retardation plate of FIG. The pattern retardation plate includes a pattern retardation layer 120 on a substrate film (for example, an optically isotropic film) 110 that is not patterned. In the pattern retardation layer 120, the first retardation regions 121 and the second retardation regions 122 are alternately arranged along the width direction. Each of the first phase difference region 121 and the second phase difference region 122 has a retardation of ¼ wavelength of visible light, and is configured such that the slow axis directions thereof are orthogonal to each other.

  The pattern phase difference plate 15 is used in, for example, a stereoscopic image display device that uses circularly polarized light. The pattern retardation plate is provided on the viewer side further than the viewing side polarizing plate of the liquid crystal display device, for example, and the slow axis direction of each of the first retardation region and the second retardation region and the absorption axis of the polarizing plate It arrange | positions so that the angle | corner with a direction may be set to +/- 45 degrees. According to such a configuration, the light emitted from the liquid crystal cell or the like becomes circularly polarized light (right circularly polarized light and left circularly polarized light) orthogonal to each other in the first phase difference region and the second phase difference region. It is injected. Each of the first region and the second region is arranged so as to correspond to the right eye region and the left eye region of the video display device, so that, for example, the video light in the right eye region is right circularly polarized light, The image light in the region reaches the viewer side as left circularly polarized light. A viewer wears stereoscopic polarized glasses composed of a right-eye viewing portion and a left-eye viewing portion and visually recognizes this image light. The right-eye viewing portion and the left-eye viewing portion of the stereoscopic polarizing glasses include circular polarizing plates that are orthogonal to each other. For example, the right-eye viewing unit is configured to absorb left circularly polarized light and transmit only right circularly polarized light, and the left-eye viewing unit absorbs right circularly polarized light and transmits only left circularly polarized light. It is configured as follows. Therefore, only the video light from the right eye region is visually recognized by the viewer's right eye, and only the video light from the left eye region is visually recognized by the left eye, so that a stereoscopic video display is realized.

  Such a pattern phase difference plate is generally manufactured by forming a pattern phase difference layer 120 or the like thereon while conveying a long base film 110 in the longitudinal direction. Therefore, the pattern optical film has the longitudinal direction of the film and the pattern extending direction parallel to each other, and alternately has first regions and second regions in the width direction of the film. When the pattern optical film is used for a stereoscopic image display device, the width of the first region and the second region is equal to the pitch of the pixels (or picture elements) of the display device, for example, about several tens μm to several hundreds μm. It is.

  When the pattern phase difference plate 15 is used as the optical film, as the position detection unit 20, one having a circularly polarizing plate 24 on the normal line of the film running surface S is suitably used as shown in FIG.

  Note that the first region and the second region are orthogonal to each other, except that the first phase difference region 121 and the second phase difference region 122 both have a retardation having a quarter wavelength of visible light. A pattern retardation plate that emits circularly polarized light can be configured. For example, a pattern retardation plate in which the slow axis directions of the first region and the second region are parallel and the retardation difference between them is an odd multiple of 1/2 of the wavelength of visible light is also a linear polarizing plate. By combining with, circularly polarized light orthogonal to each other can be emitted.

  Further, the pattern retardation plate is not limited to the one in which the first region and the second region emit circularly polarized light orthogonal to each other. For example, the retardation of the first retardation region is an odd multiple of ½ of the wavelength of visible light, and the retardation of the second retardation region is an even multiple of ½ of the wavelength of visible light (even in the case of 0). The two are configured to emit linearly polarized light orthogonal to each other.

  As described above, when the slow axis directions of the first phase difference region and the second phase difference region are orthogonal to each other, or when the difference between the retardation values is ½ times the wavelength, that is, the first phase difference. If the area and the second phase difference area have polarization characteristics that are orthogonal to each other, the position detection unit equipped with the polarization element makes the pattern boundary bright and dark (black and white (the part where light reaches the light receiving element and most of the light) It can be detected as the boundary of the part that does not reach. Therefore, the detection accuracy of the pattern boundary and the traveling correction accuracy are improved, and the occurrence frequency of defective products in which cutting lines are formed at undesired positions can be significantly reduced.

  Moreover, this invention is applicable also to pattern optical films other than a pattern phase difference plate. For example, a patterned polarizing plate patterned into a first polarizing region and a second polarizing region having different absorption axis directions can also be applied as a pattern optical film. For example, as illustrated in FIG. 13A, the pattern polarizing plate 16 includes a patterned polarizing layer 130 in which first polarizing regions 131 and second polarizing regions 132 are alternately arranged on an unpatterned base film 110. Have If the first polarizing region 131 and the second polarizing region 132 are both composed of linear polarizers and are configured so that the absorption axis directions thereof are orthogonal to each other, the first region and the second region are orthogonal to each other. Therefore, the position detection unit can detect the pattern boundary as a monochrome boundary.

  In addition, a patterned optical film in which a retardation plate and a polarizing plate are laminated is also applicable to the present invention. For example, as shown in FIG. 13B, a polarizing plate 17 with a patterned retardation layer having a patterned retardation layer 120 on an unpatterned linear polarizing plate 135, or as shown in FIG. 13C. In addition, a patterned polarizing plate 18 with a retardation plate having a patterned polarizing layer 130 on an unpatterned retardation plate 125 is also applicable to the present invention. The retardation of the retardation plate (retardation layer) is 1/4 times that of visible light in the polarizing plate with a patterned retardation layer and the retardation plate with a retardation plate. If the plate (polarizing layer) is laminated so that the angle formed with the absorption axis direction is ± 45 °, a patterned circularly polarizing plate is obtained.

  In such a patterned optical film, the pattern boundary of the pattern retardation layer or the pattern polarizing layer can be set as a detection target in the position detection step as the boundary line 105 between the first region 101 and the second region 102. Therefore, it is not necessary to separately form the first region and the second region for detecting the position of the film traveling control.

  When traveling control of the pattern optical film is performed, the boundary line 105 that is a position detection target may be a product portion of the pattern optical film or may be other than the product portion. For example, as shown in FIG. 14, the first region 101 and the second region 102 may be formed in the end portion in the width direction of the optical film, etc. separately from the pattern regions 111 and 112 that are product parts. Good. Also in this case, the first region 101 and the second region 102 can be formed at the same time when the pattern regions 111 and 112 of the product portion are formed. Further, the widths of the product portion patterns 111 and 112 and the widths of the first and second regions 101 and 102 used for position detection may be the same or different.

  When each said pattern optical film is used as an optical film, the structure of the position detection part 20 can be suitably changed according to the structure of an optical film.

  In the optical film traveling control system of the present invention, it is preferable that the position detection unit 20 is configured such that each polarizing element such as the polarizing plates 23 and 25 and the quarter wavelength plate 27 can be attached or detached or the arrangement angle can be modified. . If the presence / absence of each polarizing element and the arrangement angle can be changed, the detection accuracy of the boundary 105 can be improved according to the configuration of the optical film and the optical characteristics (polarization characteristics) of the first region and the second region. In addition, the configuration of the position detection unit can be modified. Therefore, the position detection accuracy is improved, and accordingly, the running state of the film can be controlled more accurately.

DESCRIPTION OF SYMBOLS 1: Optical film 101: 1st area | region 102: 2nd area | region 105: Pattern boundary 20: Position detection part 21: Light source 23, 25: Polarizing plate 24: Circularly polarizing plate 27: 1/4 wavelength plate 29: Light receiving part 30: Position correction mechanism 31: Drive unit 32: Guide roller 40: Control unit 50: Feeding unit 51, 52, 53, 55: Guide roller 60: Cutting processing unit 500: Optical film traveling control system C1, C2: Cutting line formation (Scheduled) position C11, C21, C31: cutting line S: film running surface V: running reference position

Claims (9)

A method for producing an optical film, wherein a long optical film is cut parallel to the longitudinal direction,
A position detection step in which the traveling position in the width direction of the optical film traveling in the longitudinal direction is detected by the position detector;
A position correcting step in which the traveling position in the width direction is corrected so that the traveling position of the optical film is kept constant in the width direction according to the detection result in the position detecting step; and the optical film is parallel to the longitudinal direction. A cutting step to be cut,
The optical film has a first region and a second region formed in parallel with the longitudinal direction, and has at least one boundary line between the first region and the second region in the width direction. ,
The first region and the second region have optical characteristics with different polarization states,
The method for producing an optical film, wherein the boundary line of the optical film is optically detected by the position detection unit based on light and darkness formed based on different polarizations.   The method for producing an optical film according to claim 1, wherein the first region and the second region of the optical film have optical characteristics in which polarization states are orthogonal to each other.   The method for producing an optical film according to claim 2, wherein the first region and the second region of the optical film are configured to emit circularly polarized light orthogonal to each other.   The method for producing an optical film according to claim 2, wherein the first region and the second region of the optical film are configured to emit linearly polarized light orthogonal to each other.   5. The method for producing a school film according to claim 3, wherein the first region and the second region of the optical film have a retardation of ¼ wavelength in which the slow axis directions are orthogonal to each other.   5. The optical film according to claim 3, wherein the first region and the second region of the optical film are parallel in the slow axis direction and the difference in retardation between the first region and the second region is an odd multiple of a half wavelength. Production method. The optical film is a laminated optical film in which a second film is laminated on a part of the width direction of the first film, and the second film has optical anisotropy,
A boundary line between the first region where the second protective film is not laminated and the second region where the second protective film is laminated is formed on the position detection unit based on different polarizations. The method for producing an optical film according to claim 1, wherein the method is optically detected by brightness and darkness. An optical film traveling control system for traveling a long optical film in parallel with a longitudinal direction, wherein the optical film has a first region and a second region formed in parallel with the longitudinal direction. And having at least one boundary line between the first region and the second region in the width direction,
A position detecting unit for detecting a traveling position in the width direction of the optical film traveling in the longitudinal direction; and a width so that the traveling position of the optical film is kept constant in the width direction according to the detection result of the position detecting unit. A position correction mechanism for correcting the traveling position of the direction,
The position detection unit includes a polarizing plate and a light receiving unit on the normal line of the optical film running surface,
An optical film travel control system configured such that a boundary line between the first region and the second region of the optical film is optically detected by light and darkness formed based on different polarized light.   The optical film travel control system according to claim 8, wherein the polarizing plate is a circularly polarizing plate.

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