JP6008758B2 - Intermediate product of optical film, optical film, image display device, and method of manufacturing optical film - 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 a region for displaying an image for the right eye and a region for displaying an image for the left eye, for example, by a band-shaped region in which the short side is vertical and the long side is horizontal. 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 on a glass substrate with controlled orientation regulating force and patterning the alignment of liquid crystals with this photo-alignment layer. 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.

  Regarding the optical compensation sheet such as this pattern retardation film, Patent Document 3 proposes that a liquid crystal layer is formed wider than an alignment layer while a long base material is conveyed, and the alignment layer is covered with the liquid crystal layer. Yes.

  However, when manufactured by the method of Patent Document 3, it was found that in the pattern retardation film, the liquid crystal layer was partially peeled to cause a defect.

JP 2005-49865 A JP 2012-042530 A Japanese Patent No. 4239872

  This invention is made | formed in view of such a condition, and it aims at preventing the fault by the partial peeling of a liquid crystal layer regarding optical films, such as a pattern phase difference film.

  The present inventor has made extensive studies to solve the above-mentioned problems, and has obtained the knowledge that a liquid crystal layer is formed narrower than the alignment layer, and has completed the present invention.

    Specifically, the present invention provides the following.

(1) An intermediate product of an optical film in which an alignment layer and a retardation layer are sequentially laminated on a transparent substrate and wound on a roll,
The retardation layer is made narrower than the alignment layer.

  According to (1), it is possible to prevent the occurrence of a portion where the retardation layer is in direct contact with the substrate, thereby preventing partial separation of the retardation layer at the portion, and as a result, a portion of the liquid crystal layer It is possible to prevent drawbacks due to typical peeling.

(2) In (1),
In the retardation layer, first and second regions having different phase differences given to transmitted light are alternately provided.

  According to (2), the defect by partial peeling of a liquid crystal layer can be prevented regarding a pattern phase difference film.

  (3) An optical film is produced from the intermediate product of the optical film as described in (1) or (2).

  According to (3), the optical film which prevents the fault by the partial peeling of a liquid crystal layer can be provided.

  (4) An image display device in which the optical film according to (3) is disposed on the front side surface of the image display panel.

  According to (4), it is possible to configure an image display device by applying an optical film that prevents defects due to partial peeling of the liquid crystal layer.

(5) In the alignment layer preparation step, the alignment layer is formed on the transparent substrate while the transparent substrate is pulled out from the roll and conveyed. In the subsequent retardation layer preparation step, the retardation layer is formed on the alignment layer. In the manufacturing method of the optical film to be produced,
The retardation layer manufacturing step includes
The retardation layer is made narrower than the alignment layer.

  According to (5), it is possible to prevent the occurrence of a portion where the retardation layer is in direct contact with the substrate, thereby preventing partial separation of the retardation layer at the portion, and as a result, a portion of the liquid crystal layer It is possible to prevent drawbacks due to typical peeling.

  ADVANTAGE OF THE INVENTION According to this invention, the fault by partial peeling of a liquid-crystal layer can be prevented regarding optical films, such as a pattern phase difference film, regarding optical films, such as a pattern phase difference film concerning a passive three-dimensional image display.

It is a figure which shows the pattern phase difference film which concerns on 1st Embodiment of this invention. It is a figure which shows the manufacturing process of the pattern phase difference film of FIG. It is a figure where it uses for description of the width | variety of each part 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, in the pattern retardation film 1, an orientation layer 3 and a retardation layer 4 are sequentially formed on one surface of a base material 2 made of a transparent film such as TAC (triacetyl cellulose) and acrylic. 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 has a right width region (first region) A and a left eye region (second region) with a certain width corresponding to the pixel assignment in the liquid crystal display panel. ) B and B are sequentially formed in a band shape, and give phase differences corresponding to light emitted from the right-eye and left-eye pixels, respectively.

  In the patterned phase difference film 1, after a photo-alignment material layer is formed of a photo-alignment material, the photo-alignment material layer is irradiated with ultraviolet rays by linearly polarized light, whereby the alignment layer 3 is formed by a photo-alignment technique. 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 pattern retardation film 1 has an AG (antiglare) layer 5 formed on the other surface of the substrate 2, and the antiglare property is achieved by the AG layer 5. The AG layer 5 is produced by directly performing AG treatment on the surface of the substrate 2, but may be produced by laminating a film having an antiglare function. Further, a so-called clear LR layer may be fabricated instead of the AG layer.

  FIG. 2 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 by a long film wound around a roll, and the AG layer 5 is produced by pulling out the base material 2 from the roll and sequentially performing AG treatment (SP1). -SP2). Subsequently, in this manufacturing process, the substrate 2 is once wound on a roll, and the substrate 2 is conveyed to the layering step of the photo-alignment layer, or the substrate 2 is directly conveyed to the layering step of the photo-alignment layer, An alignment material layer is sequentially formed (SP3). Here, although various manufacturing methods can be applied to the photo-alignment material layer, in this embodiment, a coating liquid in which the photo-alignment material is dispersed in a solvent such as benzene is applied with a die or the like, Made by drying.

  Subsequently, in this manufacturing process, a photo-alignment layer is produced by irradiating ultraviolet rays in the exposure process (SP4). 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 this manufacturing process, in the retardation layer manufacturing process, after the liquid crystal material coating liquid is applied by a die or the like, the liquid crystal material is cured by irradiation with ultraviolet rays, and the retardation layer 4 is manufactured (SP5). ). Subsequently, in the winding process (SP6), the base material 2 formed by producing the AG layer 5, the alignment layer 3, and the retardation layer 4 is wound on a roll. Thereby, the intermediate product of the pattern retardation film which is an optical film is completed.

  In this manufacturing process, the roll, which is an intermediate product, is conveyed to a cutting process and cut into a desired size to produce a pattern retardation film 1 (SP7). 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. In some cases, an adhesive layer or the like according to the arrangement on the panel surface of the liquid crystal display panel may be provided. In this case, after the adhesive layer and the separator film are provided on the base material 2 drawn from the roll, the desired size is obtained by a cutting process. It will be severed. In this manufacturing process, the pattern retardation film 1 thus produced is inspected and shipped in the product inspection process (steps SP8-SP9).

(Prevention of partial peeling)
By the way, when the base material 2 is wound on a roll in a state where the retardation layer 4 is produced in this way and processed in a subsequent process, the retardation layer 4 is partially peeled, and the material of the peeled retardation layer is changed to each part. It has been found that various defects occur due to adhesion. When this was examined in detail, when the phase difference layer 4 was produced directly on the base material 2 without using the alignment layer 3, the adhesion of the phase difference layer 4 to the base material 2 was weak, In a post-process after winding on a roll, the retardation layer 4 is partially peeled off at the location where the retardation layer 4 is directly formed on the substrate 2, thereby causing a defect due to partial peeling of the liquid crystal layer. It was found to occur. Therefore, in this embodiment, the retardation layer 4 is made narrower than the alignment layer 3 so that a portion where the retardation layer 4 is directly formed on the base material 2 does not occur, thereby generating defects. To prevent.

  FIG. 3 is a diagram illustrating a relationship in the width direction of the base material 2, the alignment layer 3, and the retardation layer 4. Here, the width of the substrate 2 is indicated by W2, the width of the alignment layer 3 is indicated by W3, and the width of the retardation layer 4 is indicated by W4. The retardation layer 4 is W3 + ΔW3 (SP3) <W2 when the maximum value of the meandering amount in the width direction of the substrate 2 generated in the transport process is ΔW3 (SP3) in the photoalignment material layer manufacturing step (SP3). Thus, the coating width of the photo-alignment material is set so that the base material 3 does not protrude in the width direction even when the base material 3 meanders.

  On the other hand, the retardation layer 4 has W4 + ΔW4 (SP5) when the maximum value of the meandering amount in the width direction of the substrate 2 generated in the conveyance process in the retardation layer production step (SP5) is ΔW4 (SP5). ) The coating width of the liquid crystal material is set so that <W3, and thus the base material 3 is produced so as not to protrude from the alignment layer 3 in the width direction even when the substrate 3 meanders. Thereby, the phase difference layer 4 is hold | maintained by the base material 2 (alignment layer 3) with sufficient adhesive force, and partial peeling is prevented.

FIG. 4 is a diagram showing test results of the coating widths W4 and W3 of the retardation layer (liquid crystal layer) 4 and the alignment layer 3. In this test, the base material 2 was a TAC film (TD60UL-P: manufactured by Fuji Film Co., Ltd.), and the back surface was subjected to AG treatment. Examples 1 to 3 and Comparative Examples 1 to 4 are cases where the substrate width (raw fabric width) W2 is 1330 mm, and Examples 5 and 6 are cases where the substrate width W2 is 1150 mm and 1490 mm, respectively. In this experiment, a coating liquid for the alignment layer 3 was applied by die coating with a width W3 shown in FIG. 3 and then irradiated with linearly polarized ultraviolet light with a light amount of 20 mJ / cm ² to produce the photo-alignment layer 3. . Furthermore, the phase difference layer 4 was produced by apply | coating a coating liquid by die coating by width W4 shown in this FIG. 3, and making it harden | cure by ultraviolet irradiation. A nematic liquid crystal layer was applied to the retardation layer 4 and the thickness was 1 μm. The number of defects was measured by visually observing a prototype with a length of 10 m, and defects having a diameter of 1000 μm or more were measured as defects. In this case, the subsequent process was a cutting process in which the film was pulled out from the roll and cut into a desired size.

  As shown in Examples 1-3, 5, and 6, when the width W4 of the retardation layer 4 is smaller than the width W3 of the alignment layer 3 in the range of 30 mm or more and 40 mm or less, the number of defects is 1. It was found that the quality was sufficient for practical use. This tendency was the same even when the width W2 of the base material was different, as can be seen from the comparison between Examples 1 to 3 and Examples 4 and 5. Further, as shown in Example 4, it was found that when the retardation layer 4 was narrowed by 50 mm with respect to the alignment layer 3, the number of defects was reduced to zero and the quality was further improved. On the other hand, as shown in Comparative Examples 1 to 4, when the width W3 of the alignment layer 3 is equal to the width W4 of the retardation layer 4, the width W4 of the retardation layer 4 is further greater than the width W3 of the alignment layer 3. It was found that when the width was wide, the number of defects was increased, and the deterioration in quality was remarkable.

  According to the above configuration, a defect due to partial peeling of the liquid crystal layer can be prevented by forming the retardation layer narrower than the alignment layer.

[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 alignment layer and the retardation layer are formed narrowly with a margin as much as the meandering amount in the width direction of the base material 2 has been described. In consideration of the number of phase difference films, the film may be made narrower.

  In the above-described embodiment, the case where the pixels for the right eye and the left eye are sequentially set in the vertical direction to produce the first and second regions in a strip shape has been described. However, 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.

  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 optical films formed by closely arranging different first and second regions, and can be widely applied to various optical films having a uniform phase difference over the entire surface.

DESCRIPTION OF SYMBOLS 1 Pattern retardation film 2 Base material 3 Orientation layer 4 Phase difference layer 5 AG layer

Claims (1)

An optical device for producing an alignment layer on the transparent substrate in the alignment layer preparation step and drawing a retardation layer on the alignment layer in the subsequent retardation layer preparation step while pulling and transporting the transparent substrate from the roll. In the film manufacturing method,
The alignment layer is a photo-alignment layer;
The retardation layer manufacturing step includes
Compared to the alignment layer, the retardation layer is made narrower,
The alignment layer preparation step includes
When the width of the transparent substrate is W2, the width of the alignment layer is W3, and the maximum value of the meandering amount in the width direction of the transparent substrate generated in the conveying process in the alignment layer manufacturing step is ΔW3,
The alignment layer is manufactured by W3 + ΔW3 <W2,
The retardation layer manufacturing step includes
When the width of the retardation layer is W4, and the maximum value of the meandering amount in the width direction of the transparent substrate generated in the transport process in the retardation layer production step is ΔW4,
The retardation layer is manufactured by W4 + ΔW4 <W3.
Manufacturing method of optical film .

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