JP6107236B2 - Optical film manufacturing method, optical film, optical film substrate and image display device - Google Patents

Description

  The present invention relates to a pattern retardation film applied to a passive three-dimensional image display.

  In recent years, flat panel displays capable of three-dimensional display have been provided. Here, in order to perform three-dimensional display on a flat panel display, it is usually necessary to selectively provide a right-eye image and a left-eye image to the viewer's right eye and left eye in some manner. . As a method for selectively providing a right-eye image and a left-eye image, for example, a passive method is known. This passive three-dimensional display method will be described with reference to the drawings. FIG. 5 is a schematic diagram showing an example of a passive three-dimensional display using a liquid crystal display panel. In the example of FIG. 5, pixels that are continuous in the vertical direction of the liquid crystal display panel are sequentially and alternately distributed to a right-eye pixel that displays a right-eye image and a left-eye pixel that displays a left-eye image. And driving with the image data for the left eye, thereby displaying the image for the right eye and the image for the left eye simultaneously. As a result, the screen of the liquid crystal display panel is alternately switched into an area for displaying an image for the right eye and an area for displaying an image for the left eye, for example, by a band-like area having a short side in the vertical direction and a long side in the horizontal direction. It is divided.

  Furthermore, in the passive method, a pattern retardation film is placed on the panel surface of the liquid crystal display panel, and light emitted from the linearly polarized light from the right-eye and left-eye pixels is converted into circularly polarized light with different rotation directions for the right-eye and left-eye. To do. Therefore, in the pattern retardation film, two types of band-like regions in which the slow axis direction (direction in which the refractive index is maximum) are orthogonal to each other are sequentially formed corresponding to the setting of the region in the liquid crystal display panel. Thus, in the passive method, glasses equipped with corresponding polarizing filters are worn, and a right-eye image and a left-eye image are selectively provided to the viewer's right eye and left eye, respectively. Here, as the slow axis direction of the adjacent band-like region, a combination of +45 degrees and −45 degrees, or 0 degrees and +90 degrees with respect to the horizontal direction is usually employed. In the example of FIG. 5, the long side direction of the screen is shown as the horizontal direction in accordance with the name in the normal image display device.

  This passive method can also be applied to a liquid crystal display device with a slow response speed, and can also display three-dimensionally with a simple configuration using a pattern retardation film and circularly polarized glasses.

  The pattern phase difference film according to this passive method requires a pattern-like phase difference layer that gives a phase difference to transmitted light corresponding to the allocation of pixels. With respect to this pattern retardation film, Patent Document 1 discloses a method of forming a retardation layer by forming a photo-alignment layer with controlled orientation regulating force on a glass substrate and patterning the alignment of liquid crystals with this photo-alignment layer. It is disclosed. Further, in Patent Document 2, a photo-alignment layer is prepared by exposing the entire surface and then exposing using a mask, and aligning and curing the liquid crystal layer by the alignment regulating force of the photo-alignment layer. A method for producing a pattern retardation film is disclosed.

  Various film materials employ various antireflection methods, and by applying a low refractive index material (a so-called clear antireflection surface material) to one of the antireflection methods, the film material is transparent. A method of reducing the reflectance while ensuring a feeling is employed. Regarding the antireflection by the clear antireflection surface material, various devices have been proposed in Patent Documents 3, 4 and the like. The antireflection by this clear surface material is achieved by creating a surface film made of a material with a low refractive index on the surface of the antireflection object so that the reflected light reflected on the front side of this surface layer and the lower side surface of this surface layer The amount of the reflected light is reduced by interference with the reflected light reflected at, thereby preventing reflection.

  By the way, in an optical film such as a pattern retardation film, it is considered that a high-quality image can be displayed by disposing it on an image display panel if antireflection is applied by applying a clear antireflection surface material. However, when applying anti-reflection surface material to the optical film such as pattern phase difference film to prevent reflection, the liquid crystal layer related to the phase difference layer should be anti-reflective when it is wound by a roll in the production process. There was a problem that the surface sticks and blocking occurs, which makes it practically not applicable to this type of optical film.

JP 2005-49865 A JP 2012-042530 A JP 2007-264421 A JP 2007-272132 A

  The present invention has been made in view of such circumstances, and in the case of optical films such as a pattern retardation film, blocking in the production process even when antireflection is applied by applying a clear antireflection surface material. It is an object of the present invention to be able to effectively avoid the occurrence of the problem.

  The present inventor has conducted extensive research to solve the above problems, and after performing antireflection treatment on the surface on one side of the substrate, a protective film is disposed, and then the retardation layer is disposed on the other surface. As a result, the present invention was completed.

    Specifically, the present invention provides the following.

(1) An antireflection layer creating step of drawing an antireflection layer on one surface side of the transparent base material by drawing a transparent base material from a roll from a roll and applying a surface material;
A protective film disposing step of disposing a protective film on the antireflection layer;
An alignment layer creating step for creating an alignment layer on the other surface side of the transparent substrate on which the protective film is arranged by the protective film arranging step;
By providing a retardation layer creating step for creating a retardation layer on the alignment layer,
An optical film is prepared from a laminate of the protective film, the antireflection layer, the transparent substrate, the alignment layer, and the retardation layer.

  According to (1), it is possible to execute post-processes such as an alignment layer creation step and a retardation layer creation step with the antireflection layer covered with a protective film, thereby applying a clear antireflection surface material to prevent reflection. Even in the case of achieving this, it is possible to effectively avoid the occurrence of blocking in the production process.

(2) In (1),
The protective film is a transparent film having a retardation value Re of 3000 nm or less and a slow axis of 45 ° ± 15 ° with respect to the slow axis of the retardation layer,
An inspection step of inspecting the optical film with transmitted light of the optical film is provided after the retardation layer creating step.

  According to (2), it is possible to further improve productivity by being able to execute a running inspection using transmitted light.

(3) An optical film raw material used for production of an optical film,
The optical film is
An orientation layer and a retardation layer are sequentially laminated on the surface of one side of the transparent substrate made of a long film, and a desired retardation is imparted to transmitted light by the retardation layer,
The optical film original fabric is
An antireflection layer and a protective film obtained by applying a surface material were sequentially laminated on the other surface of the transparent substrate, and wound on a roll.

  According to (3), the orientation layer and the retardation layer can be sequentially formed in a state where the antireflection layer is covered with the protective film, so that even when antireflection is applied by applying a clear antireflection surface material, The occurrence of blocking in the production process can be effectively avoided.

(4) In (3),
The protective film is a transparent film having a retardation value Re of 3000 nm or less and a slow axis of 45 ° ± 15 ° with respect to the slow axis of the retardation layer.

  According to (4), productivity can be further improved by being able to execute a running inspection using transmitted light.

  (5) The optical film original fabric described in (3) or (4) was prepared by creating the alignment layer and the retardation layer.

  According to (5), when a clear antireflection surface material is applied to achieve antireflection, it is possible to effectively avoid the occurrence of blocking in the production process and provide an optical film.

  (6) An image display device in which the optical film according to (5) is disposed on the panel surface of the image display panel.

  According to (6), it is possible to provide an image display device in which an optical film that effectively avoids occurrence of blocking in a production process is disposed in a configuration in which a clear antireflection surface material is applied to prevent reflection. it can.

  According to the present invention, the occurrence of blocking in the production process can be effectively avoided even when antireflection is applied by applying a clear surface material for an optical film such as a pattern retardation film. Can be.

It is a figure which shows the pattern phase difference film which concerns on 1st Embodiment of this invention. It is a figure where it uses for description of arrangement | positioning of the protective film in the pattern phase difference film of FIG. It is a figure which shows the manufacturing process of the pattern phase difference film of FIG. It is a figure which shows an experimental result. It is a figure where it uses for description of a pattern phase difference film.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing a pattern retardation film applied to the image display device according to the first embodiment of the present invention. In the image display device according to the first embodiment, the pixels of the liquid crystal display panel that are continuous in the vertical direction (the left-right direction is the corresponding direction in FIG. 1) sequentially and alternately display the right-eye image. The pixels are assigned to the left-eye pixels for displaying the left-eye image and the left-eye image, and are driven by the right-eye and left-eye image data, respectively. As a result, the image display device alternately divides the display screen into a band-like region for displaying an image for the right eye and a band-like region for displaying an image for the left eye. Display at the same time. In this image display device, a pattern phase difference film 1 is disposed on the panel surface (viewer side surface) of the liquid crystal display panel, and the pattern phase difference film 1 corresponds to light emitted from right-eye and left-eye pixels, respectively. To give the phase difference. Thereby, this image display apparatus displays a desired three-dimensional image by a passive method.

  Here, the pattern retardation film 1 has an orientation layer 3, a retardation layer 4, and a pressure-sensitive adhesive on one surface of a base material 2 made of a transparent film such as TAC (triacetyl cellulose), acrylic, and cycloolefin polymer. Layer 5 and separator film 6 are sequentially provided. The pattern retardation film 1 is peeled off from the separator film 6 to expose the pressure-sensitive adhesive layer 5, and the pressure-sensitive adhesive layer 5 is attached and held on the panel surface of the image display panel.

  In the pattern retardation film 1, a retardation layer 4 is formed of a liquid crystal material solidified (cured) while maintaining refractive index anisotropy, and the alignment of the liquid crystal material is patterned by the alignment regulating force of the alignment layer 3. . In FIG. 1, the orientation of the liquid crystal molecules is exaggerated by an elongated ellipse. By this patterning, the pattern phase difference film 1 corresponds to the allocation of pixels in the liquid crystal display panel, and has a constant width and a right eye region (first region) A and a left eye region (second region). B and B are alternately formed in a band shape, and give phase differences corresponding to light emitted from the right-eye and left-eye pixels, respectively.

  After the photo-alignment material layer is produced from the photo-alignment material, the pattern retardation film 1 is irradiated with ultraviolet rays by linearly polarized light by a so-called photo-alignment method, and thereby the photo-alignment method is applied. Thus, the alignment layer 3 is formed. Here, the ultraviolet light applied to the photo-alignment material layer is set so that the direction of polarization differs between the right-eye region A and the left-eye region B by 90 degrees, and thereby the liquid crystal material provided in the retardation layer 4 , Liquid crystal molecules are aligned in the corresponding directions in the right-eye region A and the left-eye region B, and a phase difference corresponding to transmitted light is given. In addition, although various materials to which the photo-alignment technique can be applied can be applied as the photo-alignment material, in this embodiment, the alignment is not changed by ultraviolet irradiation after the alignment, for example, a light dimerization type. Use materials. The light dimerization type material is described in “M. Schadt, K. Schmitt, V. Kozinkov and V. Chigrinov: Jpn. J. Appl. Phys., 31, 2155 (1992)”, “M. Schadt, H. Seiberle and A. Schuster: Nature, 381, 212 (1996), etc., and is already commercially available, for example, under the trade name “ROP-103” (Rolic technologies Ltd.).

  Furthermore, in this embodiment, the anti-reflection layer 7 and the protective film 8 are sequentially provided on the other surface of the substrate 2 in the pattern retardation film 1. Here, the antireflection layer 7 has a contrast by reducing the whitishness by applying an antiglare hard coat layer for preventing visibility deterioration due to reflection of external light and a so-called clear antireflection surface material. In this embodiment, transparency is ensured, the reflectance is reduced, and a high-quality image is displayed.

  The protective film 8 is disposed to prevent the antireflection layer 7 from sticking to other parts in the production process, and to prevent the pattern retardation film 1 from being damaged in the production process and the conveyance process. In this embodiment, the protective film 8 is transparent so as not to interfere with the inspection of optical characteristics (defects), which is a subsequent process, by being disposed immediately after the antireflection layer 7 is formed as described later. A film having a small orientation is applied. More specifically, a polyethylene film, a PET (Polyethylene terephthalate) film, or the like can be applied. As for the orientation, if the retardation value Re is 3000 nm or less and the slow axis is 45 ° ± 15 ° with respect to the slow axis of the retardation layer, the inspection apparatus provided in the production process is sufficient. Although it is possible to detect defects, it is more preferable that it is 2600 nm or less and that the slow axis is 45 ° ± 10 ° with respect to the slow axis of the retardation layer. In addition, as shown in FIG. 2, the extending direction of the right eye region A and the left eye region B in the retardation layer 4 of the pattern retardation film 1 (the conveyance direction MD of the base material 2) is the fast axis direction or the slow axis direction. It arrange | positions so that it may become a phase-axis direction. In FIG. 2, the fast axis direction or the slow axis direction of each region is indicated by an arrow.

  FIG. 3 is a flowchart showing manufacturing steps of the pattern retardation film 1. In the manufacturing process of the pattern retardation film 1, the base material 2 is provided to the original fabric creating process (SP 2) by a long film wound around a roll, and in this original fabric creating process, the base material 2 is drawn from the roll and processed. By doing this, the raw material used for preparation of the orientation layer 3 and the phase difference layer 4 is created.

  That is, in this raw fabric production process, in the antireflection layer production process (SP2-1), an antiglare hard coat layer and a low reflection layer are sequentially produced on the substrate 2 to produce the antireflection layer 7. In the low reflection layer, various configurations relating to the antiglare hard coat layer and the low reflection layer can be widely applied. In the original fabric creating process, the protective film 8 is arranged in the subsequent protective film arranging process SP2-2. In the subsequent winding step (SP2-3), the base material 2 provided with the antireflection layer 7 and the protective film 8 is wound into a roll. In this original fabric creating process, a series of these processes are performed by roll-to-roll, and thereby an original fabric is created with high production efficiency.

  However, although this raw fabric is processed into a patterned retardation film through successive steps such as an alignment layer creation step and a retardation layer creation step, in this embodiment, the protective film 8 is provided on the front side surface of the antireflection layer 7 in this embodiment. Can be prevented from sticking to the other part of the antireflection layer 7 even if the process such as winding, laminating, etc. is performed in the subsequent process. It can prevent and ensure high productivity.

  Further, by disposing the protective film 8 in the fast axis direction or the slow axis direction described above, in the production process, product inspection can be performed by so-called running inspection which is inspection in a state where the substrate 2 is conveyed. Therefore, high productivity can be secured.

  In addition, by arranging the protective film 8 in this way and winding it up in a roll shape, when using a substrate that is easily curled, this curling can be suppressed, and the pattern phase difference can be reduced accordingly. A film can be produced.

  Thus, the raw material wound on the roll in this way is conveyed to the alignment layer creation step (SP3), where it is drawn out from the roll to create the alignment layer 3. That is, in the alignment layer creation step, a photo-alignment material layer is prepared. Here, the production of the photo-alignment material layer can be applied to various manufacturing methods, but in this embodiment, the coating liquid in which the photo-alignment material is dispersed in a solvent such as benzene, a ketone solvent, and an ester solvent. After coating with a die or the like, it is produced by drying.

  Subsequently, in this alignment layer creation step, a photo-alignment layer is formed by irradiating ultraviolet rays in the exposure step. Here, in the exposure process, after selectively exposing the region corresponding to the right-eye region or the left-eye region by irradiating the ultraviolet light with the linearly polarized light using the mask, the ultraviolet light due to the linearly polarized light whose polarization direction is orthogonal to the entire surface. It is executed by irradiating.

  Subsequently, in the manufacturing process (SP4), after the liquid crystal material coating liquid is applied with a die or the like, the liquid crystal material is cured by irradiation with ultraviolet rays, so that the phase difference layer 4 is manufactured. The In the manufacturing process, in the subsequent inspection process (SP5), defects are inspected by so-called running inspection. Here, the running inspection is an inspection performed while conveying an inspection object in a production process or the like. In the inspection process, linear polarizing plates with a crossed Nicol arrangement are arranged above and below the substrate 2 conveyed on the production line, and the transmission axis of the linear polarizing plate is an angle of 45 degrees with respect to the conveying direction of the substrate 2. Is held. Thereby, this manufacturing process arrange | positions a linearly-polarizing plate by cross nicol arrangement | positioning so that the phase difference layer 4 formed in the base material 2 may become a quenching position. In this manufacturing process, one side of the linearly polarizing plate having the crossed Nicols arrangement is transmitted to irradiate illumination light, and the transmitted light of the other side of the linearly polarizing plate is monitored by the imaging device, whereby the base material 2 Monitor the defects while transporting. The defect detection result is used for process management and product management.

  In this manufacturing process, when the product is inspected by the so-called running inspection, the base material 2 formed by forming the AG layer 5, the alignment layer 3, and the retardation layer 4 is wound on a roll in the winding process (SP6). . Thereby, the intermediate product of the pattern retardation film which is an optical film is completed. However, when the protective film 8 is not provided when the film is wound by a roll as described above, the antireflection layer 7 is stuck to the retardation layer 4 to cause blocking, but in this embodiment, the protective film 8 is used. By being provided, sticking can be prevented. Further, the occurrence of curling due to such winding can be reduced.

  Then, this manufacturing process conveys the roll which is an intermediate product to the contact bonding layer preparation process (SP7), and arranges the pressure sensitive adhesive layer 5 and the separator film 6 here sequentially. In the subsequent cutting step (SP8), the pattern retardation film 1 is produced by cutting into a desired size. The pattern retardation film 1 may be supplied to the manufacturing process of the liquid crystal display panel by being integrated with a linearly polarizing plate disposed on the emission surface side of the liquid crystal display panel. In this case, the substrate drawn from the roll is used. After the optical functional layer related to the linearly polarizing plate is provided on the material 2, it is cut into a desired size by a cutting process.

FIG. 4 is a diagram showing experimental results such as sticking. In this test, the base material 2 is a TAC film (TD60UL-P: manufactured by Fuji Film Co., Ltd.), and the coating liquid of the alignment layer 3 (ROP-103: manufactured by Rolic technologies Ltd.) is applied and dried by die coating. Then, the alignment layer 3 was created by irradiating with ultraviolet rays by linearly polarized light with a light amount of 20 mJ / cm ² . The linearly polarized light at this time was light having an angle of ± 45 degrees with respect to the transport direction MD. Thereafter, a photopolymerizable nematic liquid crystal was applied to the retardation layer 4 so as to have a layer thickness of 1 μm.

  In FIG. 4, the surface material indicates the arrangement of the antireflection layer 7 and the like on the back surface side (the side surface opposite to the phase difference layer side surface) of the base material 2, and the clear LR is the antireflection layer 7 according to this embodiment. The case where is arranged is shown. In the example of FIG. 4, the antireflection layer 7 is obtained by applying a clear hard coat layer to the antiglare hard coat layer and applying a low refractive index layer to the low reflection layer. Clear HC is obtained by applying a clear hard coat layer to an antiglare hard coat layer. TAC (no surface material) is a case where the antireflection layer 7 is not provided.

  In the protective film, oriented PET or polyethylene film is a PET film having a retardation value of 3000 nm or less and a slow axis of 45 ° ± 15 ° with respect to the slow axis of the retardation layer, and non-oriented PET has a retardation value. The PET film has a slow axis of 3000 nm or less and a slow axis of 45 ° ± 35 ° or less with respect to the slow axis of the retardation layer.

  In FIG. 4, sticking was confirmed by visual observation under a fluorescent lamp after being wound on a roll and pulled out from the roll. A case where even part of the sticking occurs is indicated by “×”, and a case where no sticking occurs is indicated by “◯”. In the running inspection, it is visually confirmed whether or not a defect can be detected. A case where the defect can be detected is indicated by “◯”, and a case where the defect cannot be detected is indicated by “X”. For curls, the average height of the apexes of the four corners was measured for a rectangular sample with a size of 100 mm × 100 mm. Moreover, the value measured by Axostep (made by Axometrics) was used for the phase difference value and the optical axis. The optical axis (slow axis) is 0 degree in the MD direction.

  According to the measurement result of FIG. 4, according to the comparison between Examples 1 to 3 and Comparative Examples 1, 3, and 4, when the protective film is not disposed, sticking occurs, but the protective film is stuck. It turns out that it can prevent. Further, it can be seen that the curl is reduced by the arrangement of the protective film by comparing Example 3 with Comparative Example 3 and further by comparing Example 1, 2 and Comparative Example 1. Moreover, it turns out that a driving | running | working test | inspection becomes possible by the combination of the retardation value of a protective film, and a slow axis by contrast of Example 1, 2 and Comparative Example 2. FIG.

[Other Embodiments]
As mentioned above, although the specific structure suitable for implementation of this invention was explained in full detail, this invention can change the structure of the above-mentioned embodiment variously in the range which does not deviate from the meaning of this invention.

  That is, in the above-described embodiment, the case where the right and left eye pixels are sequentially set in the vertical direction to produce the first and second regions in a strip shape is described, but the present invention is not limited to this, and the right eye is used. Also, it can be widely applied to the case where the allocation of the pixels for the left eye is executed in the vertical direction and the horizontal direction, and the first and second regions are set by the arrangement of the checkered pattern in pixel units.

  In the above-described embodiment, the case where the alignment layer is formed by the photo-alignment method is described. However, the present invention is not limited to this, and the case where the alignment layer is formed by forming a fine concavo-convex shape by a shaping process. Can also be widely applied.

  Moreover, although the case where it arrange | positions to the image display panel by a liquid crystal display panel was described in the above-mentioned embodiment, this invention is not restricted to this, When arrange | positioning to the image display panel by an organic EL element, the image display panel by a plasma display, etc. Can also be widely applied.

  In the above-described embodiment, the case where the present invention is applied to the pattern retardation film applied to the passive type image display device has been described. However, the present invention is not limited to this, and the phase difference given to the transmitted light is important. The present invention can be widely applied to inspection of an optical film in which different first and second regions are closely arranged. Furthermore, it can be widely applied to various optical films having a uniform retardation over the entire surface.

DESCRIPTION OF SYMBOLS 1 Pattern phase difference film 2 Base material 3 Orientation layer 4 Phase difference layer 5 Pressure sensitive adhesive layer 6 Separator film 7 Antireflection layer 8 Protective film

Claims (4)

A process of creating an optical film,
An antireflection layer creation step of creating an antireflection layer on one surface side of the transparent substrate by drawing a transparent substrate from a roll from a roll and applying a surface material;
A protective film arrangement in which a protective film having a retardation value Re of 3000 nm or less and a transparent film having a slow axis of 45 ° ± 15 ° with respect to the slow axis of the retardation layer is disposed on the antireflection layer. Process,
An alignment layer creating step for creating an alignment layer on the other surface side of the transparent substrate on which the protective film is arranged by the protective film arranging step;
On the alignment layer, a retardation layer creating step for creating a retardation layer;
By providing an inspection step of inspecting the optical film with the transmitted light of the optical film after the retardation layer creating step,
An optical film is produced from the laminated body of the said protective film, the said reflection preventing layer, the said transparent base material, the said orientation layer, and the said phase difference layer. The manufacturing method of the optical film characterized by the above-mentioned. An optical film raw material used for production of an optical film,
The optical film is
An orientation layer and a retardation layer are sequentially laminated on the surface of one side of the transparent substrate made of a long film, and a desired retardation is imparted to transmitted light by the retardation layer,
The optical film original fabric is
On the other side surface of the transparent substrate, an antireflection layer by applying a surface material and a protective film are sequentially laminated and wound on a roll,
The protective film for optical film, wherein the protective film is a transparent film having a retardation value Re of 3000 nm or less and a slow axis of 45 ° ± 15 ° with respect to the slow axis of the retardation layer. An optical film produced by forming the alignment layer and the retardation layer on the optical film substrate according to claim 2. An image display device, wherein the optical film according to claim 3 is disposed on a panel surface of an image display panel.

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