JP2015040905A - Optical film, image display device, transfer body for optical film, manufacturing method of optical film, and manufacturing method of transfer body for optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film that has reduced a deterioration in characteristics due to change over time in a circular polarization plate using a laminate of a 1/2 wavelength retardation layer and a 1/4 wavelength retardation layer.SOLUTION: In an optical film sequentially laminating a 1/4 wavelength plate 16 and a linear polarization plate 15, the 1/4 wavelength plate 16 includes: at least a 1/2 wavelength retardation layer 19 that is formed of liquid crystal material oriented by an orientation regulation force of an orientation film 23 for the 1/2 wavelength retardation layer and provides 1/2 wavelength retardation to transmitted light; and a laminate of a 1/4 wavelength retardation layer 18 that is formed of liquid crystal material oriented by an orientation regulation force of an orientation film 22 for the 1/4 wavelength retardation layer and provides 1/4 wavelength retardation to transmitted light, and a positive C plate layer 9. The positive C plate layer 9 and 1/2 wavelength retardation layer 19 are bonded via an adhesion layer 20, and the 1/2 wavelength retardation layer 19, positive C plate layer 9, and 1/4 wavelength retardation layer 18 are provided in this order from the linear polarization plate 15 side.

Description

  The present invention relates to a circularly polarizing plate by laminating a linearly polarizing plate and a quarter-wave plate, and an optical device comprising the quarter-wave plate by laminating a half-wave retardation layer and a quarter-wave retardation layer. Related to film.

  Conventionally, regarding an image display device, a method has been proposed in which an optical film made of a circularly polarizing plate is arranged on the panel surface (viewer side surface) of an image display panel, and reflection of extraneous light is reduced by this optical film. Here, this optical film is composed of a laminate of a linear polarizing plate and a quarter-wave plate, and converts external light directed to the panel surface of the image display panel into linearly-polarized light by the linear polarizing plate, followed by a quarter-wave plate. Convert to circularly polarized light. Here, the extraneous light by the circularly polarized light is reflected by the surface of the image display panel or the like, but the rotation direction of the polarization plane is reversed during the reflection. As a result, contrary to the arrival time, this reflected light is converted into linearly polarized light in the direction shielded by the linear polarizing plate by the quarter wavelength plate, and then shielded by the subsequent linear polarizing plate. Outgoing emission is significantly suppressed.

  With regard to this optical film, Patent Document 1 and the like include a 1/2 wavelength phase difference layer that imparts a phase difference of ½ wavelength to transmitted light, and a 1 / wavelength that imparts a phase difference of ¼ wavelength to transmitted light. A method has been proposed in which a quarter-wave plate is formed by laminating four-wavelength retardation layers to use a liquid crystal material having a positive dispersion characteristic so that the quarter-wave plate functions with a reverse dispersion characteristic. Here, the reverse dispersion characteristic is a wavelength dispersion characteristic in which the phase difference in transmitted light is smaller as the wavelength is shorter.

  The half-wave retardation layer, the quarter-wave retardation layer, and the like can be produced by solidifying (curing) the liquid crystal material in a state where the liquid crystal material is aligned by the alignment regulating force of the alignment film. . More specifically, this type of retardation layer is formed by laminating a polymerizable liquid crystal monomer on an alignment film, raising the temperature to the phase transition point, and then polymerizing by ultraviolet irradiation or the like to fix the alignment state of the liquid crystal. Can be produced. In addition, the alignment film can be produced by transferring a fine line-shaped uneven shape produced on the shaping mold by a shaping process using the shaping mold, for example, or by a so-called photo-alignment technique. Can also be made.

  By the way, after a ½ wavelength phase difference layer and a ¼ wavelength phase difference layer are separately produced, and then bonded together by an adhesive layer, a laminate of a ½ wavelength phase difference layer and a ¼ wavelength phase difference layer is obtained. Thus, it is considered that a quarter wavelength plate can be produced. Moreover, it is thought that the whole thickness can be made thin by integrating the laminated body of this 1/2 wavelength phase difference layer and a 1/4 wavelength phase difference layer with a linear polarizing plate by the transfer method. The transfer method refers to, for example, when a desired layer is formed on a base material, the layer is not directly formed on the base material, but can be peeled once on a releasable support. After forming the transfer body by laminating the layers, the layer formed on the support is finally placed on the substrate (transfer base material) on which the layer is to be laminated according to the process, demand, etc. In this method, a desired layer is formed on the substrate by bonding and laminating, and then peeling and removing the support.

  In a circularly polarizing plate using a laminate of a ½ wavelength retardation layer and a ¼ wavelength retardation layer produced as described above, it is naturally required to reduce deterioration of characteristics due to changes with time.

JP-A-10-68816 JP 2000-284126 A

  The present invention has been made in view of such circumstances, and in a circularly polarizing plate using a laminate of a ½ wavelength phase difference layer and a ¼ wavelength phase difference layer, the deterioration of characteristics due to changes with time is reduced. The purpose is to do.

  The present inventor has made extensive studies in order to solve the above problems, and has a field of view by laminating a ½ wavelength phase difference layer and a ¼ wavelength phase difference layer with an adhesive layer with a positive C plate layer interposed therebetween. By improving the angular characteristics and further providing a positive C plate layer on the 1/4 wavelength phase difference layer side of the adhesive layer, the positive C plate layer prevents characteristic deterioration of the 1/4 wavelength phase difference layer due to the adhesive layer, This led to the idea of reducing characteristic deterioration such as reflection luminance and color due to changes over time, and the present invention was completed.

  (1) In an optical film in which a quarter-wave plate and a linear polarizing plate are sequentially laminated, the quarter-wave plate is made of at least a liquid crystal material that is aligned by the alignment regulating force of the alignment film for a half-wave retardation layer. Formed and formed of a liquid crystal material that is aligned by the alignment regulating force of the alignment layer for the ¼ wavelength phase difference layer and a ½ wavelength phase difference layer that imparts a phase difference of ½ wavelength to the transmitted light, and is transmitted A quarter wavelength retardation layer that imparts a phase difference corresponding to ¼ wavelength to the light, and a laminate of a positive C plate layer, and the positive C plate layer and the ½ wavelength retardation layer include: The ½ wavelength retardation layer, the positive C plate layer, and the ¼ wavelength retardation layer were provided by bonding with an adhesive layer from the linearly polarizing plate side.

  According to (1), the ½ wavelength phase difference layer and the ¼ wavelength phase difference layer are laminated by the adhesive layer with the positive C plate layer interposed therebetween, thereby improving the viewing angle characteristics and the overall thickness. Can be made thinner. Further, the positive C plate layer is provided on the 1/4 wavelength phase difference layer side of the adhesive layer, so that the positive C plate layer functions as a protective layer for the 1/4 wavelength phase difference layer, and the adhesive layer has a 1 The fall of the retardation value of a / 4 wavelength phase difference layer can be prevented. Here, in the case where the positive C plate layer is provided on the ¼ wavelength phase difference layer side of the adhesive layer in this way, the retardation value is lowered in the ½ wavelength phase difference layer due to the residual solvent of the adhesive layer. However, the deterioration of the characteristics of the entire quarter-wave plate due to the decrease in the retardation value of the half-wave retardation layer is that the retardation value of the half-wave retardation layer is equal to the retardation value of the quarter-wave retardation layer. By being almost doubled, the positive C plate layer is provided on the ½ wavelength phase difference layer side and the retardation value is reduced in the ¼ wavelength phase difference layer. As a result, compared to the case where the positive C plate layer is disposed on the side opposite to the half-wavelength phase difference layer side, characteristic deterioration such as an increase in reflected luminance and a change in color (color coordinate) due to a change with time is reduced. can do.

(2) In (1),
An antireflection coating layer and / or a hard coating layer was provided on the side surface of the linear polarizing plate opposite to the quarter-wave plate.

  According to (2), with respect to the optical film provided with the antireflection coating layer and / or the hard coating layer, the viewing angle characteristics are improved and the deterioration of the optical characteristics due to changes over time is reduced while reducing the overall thickness. be able to.

  (3) The image display apparatus which has arrange | positioned the optical film as described in (1) or (2) on the image display panel surface by the adhesion layer.

  According to (3), it is possible to prevent reflection with an optical film that improves the viewing angle characteristics while reducing the overall thickness and reduces deterioration of characteristics due to changes over time.

(4) A transfer body for an optical film comprising a support substrate and a transfer layer,
The transfer layer is from the support substrate side,
The 1/4 wavelength phase difference layer formed of a liquid crystal material aligned by the alignment regulating force of the 1/4 wavelength phase difference layer alignment layer, and imparting a phase difference of 1/4 wavelength to transmitted light;
A positive C plate layer;
An adhesive layer with an adhesive;
A ½ wavelength retardation layer that is formed of a liquid crystal material that is aligned by the alignment regulating force of the alignment film for the ½ wavelength retardation layer and that sequentially imparts a ½ wavelength phase difference to the transmitted light is sequentially provided. And
The 1/2 wavelength phase difference layer and the laminate of the positive C plate layer and the 1/4 wavelength phase difference layer were bonded together by the adhesive layer.

  According to (4), the ½ wavelength phase difference layer and the ¼ wavelength phase difference layer are laminated by the adhesive layer with the positive C plate layer interposed therebetween, thereby improving the viewing angle characteristics and the overall thickness. Can be made thinner. Further, the positive C plate layer is provided on the 1/4 wavelength phase difference layer side of the adhesive layer, so that the positive C plate layer functions as a protective layer for the 1/4 wavelength phase difference layer, and the adhesive layer has a 1 The fall of the retardation value of a / 4 wavelength phase difference layer can be prevented. Here, in the case where the positive C plate layer is provided on the 1/4 wavelength retardation layer side of the adhesive layer as described above, although the retardation value is reduced in the 1/2 wavelength retardation layer due to the residual solvent of the adhesive layer, The deterioration of the characteristics of the entire quarter-wave plate due to the decrease in the retardation value of the half-wave retardation layer is small as compared with the case where the retardation value is lowered in the quarter-wave retardation layer. As a result, compared to the case where the positive C plate layer is disposed on the side opposite to the half-wavelength phase difference layer side, characteristic deterioration such as an increase in reflected luminance and a change in color (color coordinate) due to a change with time is reduced. can do.

(5) In (4),
The transfer layer is
The alignment layer for the ½ wavelength retardation layer is provided on the side surface opposite to the adhesive layer of the ½ wavelength retardation layer.

  According to (5), it is possible to effectively avoid damage to the ½ wavelength retardation layer by causing the ½ wavelength retardation layer alignment film to function as a protective layer.

(6) In (4) or (5),
The transfer layer is
The alignment film for a quarter-wave retardation layer is provided on the side surface of the quarter-wave retardation layer opposite to the adhesive layer.

  According to (6), the quarter-wave retardation layer alignment film can function as a protective layer, and damage to the quarter-wave retardation layer can be effectively avoided.

(7) An optical film transfer body producing step for producing an optical film transfer body,
A bonding step according to a linearly polarizing plate, wherein the optical film transfer body is bonded to a linearly polarizing plate to produce a laminate of the optical film transfer body and the linearly polarizing plate;
A support substrate peeling step in which the support substrate of the optical film transfer member is peeled from the laminate of the optical film transfer member and the linearly polarizing plate, and the adhesive layer and the separator film are sequentially disposed,
The transfer film production process for the optical film,
An alignment film for a quarter-wave retardation layer related to a quarter-wave retardation layer on the support substrate, and a liquid crystal material aligned by an alignment regulating force of the alignment film for the quarter-wave retardation layer The quarter-wave retardation layer and the positive C-plate layer are sequentially formed to provide a quarter-wave phase difference to the transmitted light to produce a laminate on the quarter-wave retardation layer side. Producing a quarter-wave retardation layer,
By the alignment regulating force of the alignment film for 1/2 wavelength retardation layer and the alignment film for 1/2 wavelength retardation layer related to the 1/2 wavelength retardation layer on the substrate on the 1/2 wavelength retardation layer side A layered body on the ½ wavelength phase difference layer side is prepared by sequentially producing the ½ wavelength phase difference layer formed of an aligned liquid crystal material and imparting a phase difference of ½ wavelength to transmitted light. A step of producing a half-wave retardation layer;
A bonding step of the optical film transfer body, wherein the half-wave retardation layer and the positive C plate layer are bonded together by an adhesive layer to produce the optical film transfer body.

  According to (7), the ½ wavelength phase difference layer and the ¼ wavelength phase difference layer are laminated by the adhesive layer with the positive C plate layer interposed therebetween, thereby improving the viewing angle characteristics and improving the overall thickness. Can be made thinner. Further, the positive C plate layer is provided on the 1/4 wavelength phase difference layer side of the adhesive layer, so that the positive C plate layer functions as a protective layer for the 1/4 wavelength phase difference layer, and the adhesive layer has a 1 The fall of the retardation value of a / 4 wavelength phase difference layer can be prevented. Here, in the case where the positive C plate layer is provided on the ¼ wavelength retardation layer side of the adhesive layer in this way, the retardation value is reduced in the ½ wavelength retardation layer due to the residual solvent of the adhesive layer. However, the deterioration of the characteristics of the quarter-wave plate as a whole due to the decrease in the retardation value of the half-wave retardation layer is small as compared with the case where the retardation value is lowered in the quarter-wave retardation layer. As a result, compared to the case where the positive C plate layer is arranged on the side opposite to the half-wavelength retardation layer side, the increase in reflection luminance and the deterioration of the color (color coordinate) characteristics due to changes over time can be reduced. it can.

(8) A liquid crystal aligned on a support base material by an alignment film for a 1/4 wavelength retardation layer according to a 1/4 wavelength retardation layer and an alignment regulating force of the alignment film for a 1/4 wavelength retardation layer. The 1/4 wavelength phase difference layer that is made of a material and imparts a phase difference corresponding to 1/4 wavelength to transmitted light, and a positive C plate layer are sequentially manufactured, and the laminate on the 1/4 wavelength phase difference layer side A step of producing a quarter-wave retardation layer for producing
An alignment film for a 1/2 wavelength retardation layer according to a 1/2 wavelength retardation layer on the substrate on the 1/2 wavelength retardation layer side, and an alignment regulating force of the alignment film for the 1/2 wavelength retardation layer A layered body on the ½ wavelength phase difference layer side is prepared by sequentially producing the ½ wavelength phase difference layer, which is formed of a liquid crystal material aligned by the above, and imparts a phase difference of ½ wavelength to transmitted light. A step of producing a ½ wavelength retardation layer,
A bonding step according to a quarter-wave plate for producing a quarter-wave plate by bonding the half-wave retardation layer and the positive C plate layer with an adhesive layer;
From the quarter-wave plate, the base material on the half-wavelength retardation layer side, or the laminate of the base material on the half-wavelength retardation layer side and the alignment film for the half-wavelength retardation layer A peeling step of peeling and producing a transfer body for an optical film.

  According to (8), a ½ wavelength phase difference layer and a ¼ wavelength phase difference layer are laminated by an adhesive layer with a positive C plate layer in between, thereby improving viewing angle characteristics and increasing the overall thickness. Can be made thinner. Further, the positive C plate layer is provided on the 1/4 wavelength phase difference layer side of the adhesive layer, so that the positive C plate layer functions as a protective layer for the 1/4 wavelength phase difference layer, and the adhesive layer has a 1 The fall of the retardation value of a / 4 wavelength phase difference layer can be prevented. Here, in the case where the positive C plate layer is provided on the ¼ wavelength phase difference layer side of the adhesive layer in this way, the retardation value is lowered in the ½ wavelength phase difference layer due to the residual solvent of the adhesive layer. However, the deterioration of the characteristics of the entire quarter-wave plate due to the decrease in the retardation value of the half-wave retardation layer is that the retardation value of the half-wave retardation layer is equal to the retardation value of the quarter-wave retardation layer. By being almost doubled, the positive C plate layer is provided on the ½ wavelength phase difference layer side and the retardation value is reduced in the ¼ wavelength phase difference layer. As a result, compared to the case where the positive C plate layer is arranged on the side opposite to the half-wavelength retardation layer side, the increase in reflection luminance and the deterioration of the color (color coordinate) characteristics due to changes over time can be reduced. it can.

  The present invention relates to a circularly polarizing plate using a laminate of a half-wavelength retardation layer and a quarter-wavelength retardation layer, improving the viewing angle characteristics while reducing the overall thickness, and optical characteristics over time. Can be reduced.

It is sectional drawing which shows the image display apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the optical film applied to the image display apparatus of FIG. It is a figure where it uses for description of the optical film of FIG. It is sectional drawing which shows the transfer film which concerns on the optical film of FIG. It is a figure where it uses for description of the manufacturing process of the transfer film of FIG. It is a figure where it uses for description of the manufacturing process of the optical film by the transfer film of FIG. It is a figure where it uses for description of the process of the continuation of FIG.

[First Embodiment]
[Optical film and image display device]
FIG. 1 is a diagram showing an image display apparatus according to the first embodiment of the present invention. In the image display device 11, an optical film 13 is disposed on the panel surface (viewer side surface) of the image display panel 12. Here, the image display panel 12 is an organic EL panel, for example, and displays a desired color image. Note that the image display panel 12 is not limited to the organic EL panel, and various image display panels such as a liquid crystal display panel can be widely applied.

  FIG. 2 is a cross-sectional view showing the optical film 13. The optical film 13 is an optical film that suppresses reflection of extraneous light arriving at the image display panel 12 by the function of a circularly polarizing plate. For this reason, the optical film 13 is configured by laminating a linear polarizing plate 15 and a quarter-wave plate 16. The optical film 13 is peeled off the separator film to expose the pressure-sensitive adhesive pressure-sensitive adhesive layer 14, and is then adhered and held on the panel surface of the image display panel 12 by the pressure-sensitive adhesive layer 14. In addition, it may replace with a pressure sensitive adhesive and may arrange | position the optical film 13 with another adhesive, Furthermore, you may affix by the adhesive layer by an adhesive agent.

  The linear polarizing plate 15 and the quarter wavelength plate 16 are integrated with each other through the adhesive layer 17. Here, the adhesive layer 17 only needs to be able to secure a practically sufficient adhesive force. For example, although an adhesive of an ultraviolet curable resin or a thermosetting resin can be widely applied, the viewpoint of reducing the overall thickness From the viewpoint of effectively avoiding the retardation drop of the half-wave retardation layer 19 caused by the adhesive layer 17, it is preferable to apply an ultraviolet curable resin, and in this case, it is produced with a thickness of about 1 μm. Can do. Further, instead of the adhesive layer 17, an adhesive layer may be applied.

  The quarter wavelength plate 16 includes a quarter wavelength retardation layer 18 that imparts a phase difference of ¼ wavelength to transmitted light, and a ½ wavelength that imparts a phase difference of ½ wavelength to the transmitted light. The phase difference layer 19 and the adhesive layer 20 are laminated layers. Thereby, the optical film 13 sufficiently suppresses reflection of extraneous light in a wide wavelength band used for displaying a color image.

  More specifically, the ¼ wavelength plate 16 is formed from the image display panel 12 side by using the ¼ wavelength phase difference layer alignment film 22 for the production of the ¼ wavelength phase difference layer 18. The alignment layer 23 for 1/2 wavelength phase difference layers used for preparation of the layer 18, the positive C plate layer 9, the adhesive layer 20, the 1/2 wavelength phase difference layer 19, and the 1/2 wavelength phase difference layer 19 is sequentially provided. Thereby, the quarter-wave plate 16 causes the quarter-wave retardation layer 18 and the quarter-wave retardation layers 18 and 1 to function as the protective layer by using the quarter-wave retardation layer alignment film 22 and the half-wave retardation layer alignment film 23. / Scratches of the two-wavelength retardation layer 19 are reduced.

  As a result, in the image display device 11, the quarter wavelength retardation layer 18, the half wavelength retardation layer 19, and the linear polarizing plate 15 are sequentially arranged from the display screen side of the image display panel 12, as shown in FIG. 3. Thus, the slow axes (indicated by arrows respectively) of the ½ wavelength retardation layer 19 and the ¼ wavelength retardation layer 18 are counterclockwise with respect to the absorption axis of the linearly polarizing plate 15 indicated by the arrows. Are arranged at an angle of 15 degrees and 73 degrees.

  The quarter-wave retardation layer alignment film 22 and the half-wave retardation layer alignment film 23 are formed by forming fine line-shaped uneven shapes on the surface, and the alignment regulation by the fine line-shaped uneven shapes. The liquid crystal material related to the quarter-wave retardation layer 18 is aligned by force. The alignment film 22 for quarter-wave retardation layer has a ten-point average roughness (Rz) of 10 nm or more and 45 nm or less, and an average surface roughness (Ra) of 1 nm or more and 4 nm or less. . Thereby, the alignment film 22 for 1/4 wavelength phase difference layer and the alignment film 23 for 1/2 wavelength phase difference layer ensure sufficient adhesion strength with the corresponding 1/4 wavelength phase difference layer 18, Variations in the quarter-wave retardation layer 18 and the half-wave retardation layer 19 related to so-called black luminance can be sufficiently reduced.

  In this embodiment, the quarter-wave retardation layer alignment film 22 and the half-wave retardation layer alignment film 23 are formed after the forming resin layer to be used for forming a fine uneven shape, A fine line-shaped uneven shape is formed on the surface of the shaped resin layer by a shaping treatment. In this embodiment, an ultraviolet curable resin is applied to the shaping resin, and an acrylic ultraviolet curable resin is used. However, the present invention is not limited to this, and various resins used for the shaping process can be widely applied. it can.

  Further, the fine concavo-convex shape relating to the alignment film 22 for ¼ wavelength phase difference layer and the alignment film 23 for ½ wavelength phase difference layer is formed by a line-shaped (line) concavo-convex shape extending in one direction. The direction extending in one direction is formed so as to be directions that form angles of 15 degrees and 73 degrees counterclockwise with respect to the transmission axis of the linear polarizing plate 15, respectively.

  The quarter-wave retardation layer 18 and the half-wave retardation layer 19 are made of a liquid crystal material that is solidified (cured) while maintaining refractive index anisotropy by the orientation regulating force of the corresponding orientation films 22 and 23. It is formed. More specifically, the quarter-wave retardation layer 18 and the half-wave retardation layer 19 are formed by laminating a polymerizable liquid crystal monomer on the alignment films 22 and 23, and then raising the temperature to the phase transition point. It is produced by polymerizing a polymerizable liquid crystal monomer by irradiation to fix the alignment state of the liquid crystal. Although the ¼ wavelength retardation layer 18 and the ½ wavelength retardation layer 19 can widely apply various liquid crystal materials applicable to this type of optical film, in this embodiment, the same material is used. Applied. More specifically, for example, the compounds represented by the following chemical formulas (1) to (13) are used for the quarter-wave retardation layer 18 and the half-wave retardation layer 19.

  Although the adhesive layer 20 can widely apply various adhesives such as an ultraviolet curable resin and a thermosetting resin agent, it is an ultraviolet curable resin from the viewpoint of reducing the overall thickness and reducing retardation drops. In this case, it can be produced with a thickness of about 1 μm. In this embodiment, an ultraviolet curable resin applied to the preparation of the alignment film is applied.

  The linearly polarizing plate 15 is provided with the optical functional layer 15B after the lower surface side of the base material 15A made of a transparent film such as TAC (triacetylcellulose) is saponified. In addition, 15 A of base materials replace with this, poly (meth) methyl acrylate, poly (meth) butyl acrylate, methyl (meth) acrylate- (meth) butyl acrylate copolymer, (meth) acrylate methyl- A resin such as an acrylic resin such as a styrene copolymer, a glass such as soda glass, potash glass, lead glass, or quartz glass can be used.

  The optical functional layer 15B is a part that bears an optical function as a linearly polarizing plate, and is produced, for example, by adsorbing and orienting iodine compound molecules on a film material made of polyvinyl alcohol (PVA).

  Thus, in the optical film 13, by configuring the quarter wavelength plate 16 with a laminate in which the quarter wavelength retardation layer 18 and the half wavelength retardation layer 19 are bonded by the adhesive layer 20, respectively. The ¼ wavelength retardation layer 18 and the ½ wavelength retardation layer 19 produced by separate processes can be used, and thereby, an alignment film and a retardation layer are sequentially laminated. In this case, it can be produced by effectively avoiding shortage of adhesion and insufficient adhesion, and as a result, it can be produced stably and with high reliability.

  In the optical film 13, an antireflection coating layer, a hard coating layer, an antireflection coating layer, and a hard coating layer are formed on the side surface opposite to the optical functional layer 15B of the base material 15A provided on the linear polarizing plate 15, as necessary. Various functional layers 10 such as a laminate are provided.

[Positive C plate layer]
In the optical film 13, the quarter-wave plate 16, which is a laminate of the quarter-wave retardation layer 18 and the half-wave retardation layer 19, is laminated with the linearly polarizing plate 15. The C plate layer 9 is disposed between the quarter wavelength retardation layer 18 and the half wavelength retardation layer 19. Here, the positive C plate layer 9 is an optical functional layer that functions as a positive C plate by controlling the thickness direction retardation. The positive C plate is represented by nx = ny <nz, where the refractive index in the in-plane direction is nx, ny (nx ≧ ny), and the refractive index in the thickness direction is nz. With this positive C plate layer 9, the optical film 13 can improve viewing angle characteristics. More specifically, the optical film 13 can bring the optical characteristic in the oblique direction closer to the optical characteristic in the front direction, and as a result, the viewing angle characteristic is improved by bringing the reflectance in the oblique direction closer to the reflectance in the front direction. can do.

  Further, in this embodiment, the optical film 13 is provided with the positive C plate layer 9 on the side of the half-wave retardation layer 19 of the adhesive layer 20, thereby increasing the reflection luminance and color (color coordinates) due to change over time. Degradation of characteristics such as changes in

  That is, when the quarter-wave retardation layer 19 and the half-wave retardation layer 19 are bonded directly by the adhesive layer 20, although the overall thickness can be reduced, the residual solvent is eluted from the adhesive layer 20. The retardation value decreases in the quarter wavelength retardation layer 19 and the half wavelength retardation layer 19. As a result, the reflection luminance increases due to the change with time, and further the color changes.

  However, in this embodiment, by arranging the positive C plate layer 9 between the quarter wavelength retardation layer 19 and the half wavelength retardation layer 19, the quarter wavelength retardation layer 19 and the half wavelength retardation layer 19 are arranged. The positive C plate layer 9 is made to function as a protective layer for any one of the phase difference layers 19, and the retardation value of the phase difference layers 18, 19 on this one side is reduced due to the elution of residual solvent from the adhesive layer. Can be prevented.

  That is, when the positive C plate layer 9 is disposed on the 1/4 wavelength phase difference layer 18 side of the adhesive layer 20, it can function as a protective layer of the 1/4 wavelength phase difference layer 18, and the 1/4 wavelength level layer is provided. The retardation value of the retardation layer 18 can be prevented from decreasing due to the elution of residual solvent from the adhesive layer 20. On the contrary, when the positive C plate layer 9 is disposed on the 1/2 wavelength retardation layer 19 side of the adhesive layer 20, the positive C plate layer 9 is disposed on the protective layer of the 1/2 wavelength retardation layer 19. It is possible to prevent the retardation value of the ½ wavelength retardation layer 19 from decreasing due to the elution of the residual solvent from the adhesive layer 20.

  However, in any of these cases, the retardation value of the remaining one side retardation layer 19 or 18 is lowered due to aging due to elution of the residual solvent from the adhesive layer 20. However, the amount of such retardation value decrease is the same in the quarter-wave retardation layer 19 and the half-wave retardation layer 19, but the half-wave retardation layer 19 is a quarter-wave retardation layer. Since the thickness is larger than that of 19 (the retardation value is large), the influence of the quarter-wave retardation layer 19 is large.

  Accordingly, the positive C plate layer 9 is placed on the 1/4 wavelength retardation layer 18 side of the adhesive layer 20 as compared with the case where the positive C plate layer 9 is arranged on the 1/2 wavelength retardation layer 19 side of the adhesive layer 20. In the case of the arrangement, an increase in reflection luminance and a change in color due to a change with time can be reduced, and as a result, characteristic deterioration due to a change with time can be reduced.

  The positive C plate layer 9 is produced by applying a coating liquid on the ½ wavelength retardation layer 19 and drying and curing it. In addition, in this coating liquid, for example, a liquid crystal material applicable to a positive C plate such as RMM28, which is a liquid crystal material manufactured by Merck Co., can be prepared by using a solvent. The positive C plate layer 9 is prepared by forming an alignment film for a positive C plate on the half-wave retardation layer 19 and then applying a coating solution for the positive C plate, followed by drying and curing. It can also be produced.

[Transcript]
In the optical film 13, the quarter-wave plate 16 and the linear polarizing plate 15 are integrated by the adhesive layer 17, and the transfer method is applied to a series of processes related to this integration. Thereby, in this embodiment, the substrate to be transferred is the linear polarizing plate 15, and the layers (transfer layers) used for transfer are the quarter-wave retardation layer alignment film 22 and the quarter-wave retardation layer 18. , A positive C plate layer 9, an adhesive layer 20, a ½ wavelength phase difference layer 19, and a ½ wavelength phase difference layer alignment film 23.

  FIG. 4 is a diagram showing a configuration of a transfer film 21 which is this transfer body. The transfer film 21 is formed on a support substrate 25, a quarter wavelength retardation layer alignment film 22, a quarter wavelength retardation layer 18, a positive C plate layer 9, an adhesive layer 20, a half wavelength retardation. A layer alignment film 23 and a substrate 24 are provided.

  Here, the support base material 25 is a base material that is detachably supported after the transfer layer is detachably supported and the transfer layer is bonded and laminated on the transfer target substrate. In this embodiment, a PET (Polyethylene terephthalate) film, which is a transparent film material, is applied. The PET film is subjected to corona treatment as necessary, whereby the adhesion force is appropriately set. The support substrate 25 may be a resinous film material made of a resin such as a polyester resin such as polybutylene terephthalate or polyethylene aphthalate, or a polyolefin resin such as polypropylene or polymethylpentene.

  When the peelability from the transfer layer is insufficient, the support base material 25 is provided with a release layer that promotes peeling on the transfer layer side. Here, the release layer can be applied with a material having relatively high adhesion to the support substrate 25 (low peelability) and low adhesion to the transfer layer (high peelability). . In this embodiment, the lowermost layer of the transfer layer is an alignment film 22 for a quarter wavelength retardation layer made of an ultraviolet curable resin. Polymer compound), fluorine-based resin, melamine resin, epoxy resin, or a mixture of these resins and other resins (acrylic resin, cellulose-based resin, polyester resin, etc.) as appropriate.

  Incidentally, when the peelability by the release layer is insufficient, a release layer may be provided between the support substrate 25 and the release layer, and this release layer may be used to supplement the peelability by the release layer. . For the release layer, a material having relatively low adhesion to the support film (high peelability) and high adhesion to the release layer (low peelability) can be applied. More specifically, in this embodiment, the release layer includes an acrylic resin, a cellulose resin, a polyester resin, a urethane resin, a vinyl chloride-vinyl acetate copolymer, or a mixture of two or more selected from the above. Alternatively, a mixture of one or more selected from the above and other resins can be applied.

  The base material 24 is a base material that carries the transfer layer (in this case, the ½ wavelength retardation layer 19) so as to be peelable, and is subjected to peeling and removal as appropriate at the time of transfer or the like. In this embodiment, it is configured the same as the support base material 25. Moreover, also in the base material 24, in order to set appropriately the contact | adhesion power with the alignment film 23 for lower layer 1/2 wavelength phase difference layers, a corona process is performed as needed, and contact | adhesion power is improved.

〔Manufacturing process〕
FIG. 5 is a diagram for explaining the manufacturing process of the transfer film 21. In this manufacturing process, a half-wave retardation layer alignment film 23 and a half-wave retardation layer 19 are formed on the substrate 24 (FIG. 5A). That is, in this manufacturing process, the base material 24 is pulled out from the supply reel, applied with an ultraviolet curable resin coating solution with a die or the like, and then dried in a drying furnace. Note that the coating of the coating liquid is not limited to using a die, and various methods can be applied. Subsequently, in this manufacturing process, an ultraviolet curable resin is applied to a roll plate which is a mold for molding in which the line-shaped unevenness shape related to the alignment film 23 for the half-wavelength retardation layer is formed on the peripheral side surface. The processed base material 24 is pressed by a pressure roller, and the ultraviolet curable resin is cured by irradiation of ultraviolet rays by an ultraviolet irradiation device made of a high-pressure mercury lamp. Thereby, a manufacturing process transfers the uneven | corrugated shape formed in the surrounding side surface of a roll plate to the base material 24, and produces the alignment film 23 for 1/2 wavelength phase difference layers. Thereafter, the substrate 24 is peeled off together with the ultraviolet curable resin cured from the roll plate by a peeling roller, and a coating liquid of a liquid crystal material is applied by a die or the like. Then, after drying in a drying furnace, the liquid crystal material is cured by irradiating with an ultraviolet ray by an ultraviolet ray irradiating device and wound on a take-up reel. By this series of treatments, the half-wave retardation layer alignment film 23 and the half-wave retardation layer 19 are formed on the substrate 24.

  Moreover, this manufacturing process produces the quarter wavelength phase difference layer oriented film 22, the quarter wavelength phase difference layer 18, and the positive C plate layer 9 on the base material 25 (FIG. 5B). That is, in this manufacturing process, similarly, the base material 25 is pulled out from the supply reel, coated with an ultraviolet curable resin coating solution with a die or the like, dried in a drying furnace, and ¼ wavelength phase difference with a roll plate. A layer alignment film 22 is prepared. Thereafter, the liquid crystal material is applied and dried, and then the liquid crystal material is cured. Furthermore, after applying the coating liquid which concerns on the positive C plate layer 9, it dries and hardens | cures, and, thereby, the positive C plate layer 9 is produced.

  In the manufacturing process, the optical characteristics of the ½ wavelength retardation layer 19 and the ¼ wavelength retardation layer 18 are inspected by transmitted light, respectively, and then the positive C plate layer 9 and the ½ wavelength retardation layer are adhered by the adhesive layer 20. 19 are bonded together, thereby producing a transfer film 21 (FIG. 5C).

  When the half-wave retardation layer 19 and the quarter-wave retardation layer 18 are individually produced and integrated as in this embodiment, the half-wave retardation layers 19 and 1 / The optical characteristics of the four-wavelength retardation layer 18 can be inspected. As a result, the quality can be improved and the optical film 13 can be produced stably.

  FIG. 6 is a diagram for explaining the manufacturing process of the optical film 13 that follows. In this manufacturing process, after the base material 24 is peeled from the transfer film 21 (FIG. 6A), it is attached to the linearly polarizing plate 15 via the adhesive layer 17 (FIG. 6B), whereby the optical film 13 is produced. In addition, the process of peeling this base material 24 may be provided in the manufacturing process of the optical film 13 or may be provided in the manufacturing process of the transfer film 21.

  Subsequently, as shown in FIG. 7, this step is performed after the support base material 25 is peeled from the optical film 13 (FIG. 7A), and then the adhesive layer 14 and the separator film are arranged to have a desired size. The optical film 13 is produced by cutting. In the subsequent manufacturing process of the image display device 11, in the final process, the separator film is peeled to expose the adhesive layer 14, and the optical film 13 is attached to the panel surface of the image display panel 12 through the adhesive layer 14 (FIG. 7). (B)). In addition, you may perform the process which peels the support body base material 25 in the manufacturing process of an image display apparatus.

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

  That is, in the above-described embodiment, the case where the transfer layer includes the quarter wavelength retardation film and the half retardation film is described. However, the present invention is not limited to this, and the quarter wavelength film. The alignment film for phase difference and / or the alignment film for half phase difference may be peeled off integrally with the substrate so as not to be included in the transfer layer.

  In the above-described embodiment, the case where the quarter wavelength phase difference alignment film and the half phase difference alignment film are produced by the shaping process has been described. However, the present invention is not limited to this, and the photo alignment film is used. The present invention can also be widely applied to the production of these ¼ wavelength phase difference alignment films and ½ phase difference alignment films.

9 Positive C plate layer 11, 71 Image display device 12 Image display panel 13, 73 Optical film 14 Adhesive layer 15 Linearly polarizing plate 15A, 24, 25 Base material 17, 20 Adhesive layer 21 Transfer film 23 1/2 wavelength retardation layer Alignment film (alignment film)
19 1/2 wavelength retardation layer 22 Alignment film for 1/4 wavelength retardation layer (alignment film)
18 1/4 wavelength phase difference layer 16 1/4 wavelength plate 15B Optical functional layer

Claims (8)

In an optical film in which a quarter wave plate and a linear polarizing plate are sequentially laminated,
The quarter-wave plate is at least
A ½ wavelength retardation layer that is formed of a liquid crystal material that is aligned by the alignment regulating force of the alignment film for the ½ wavelength retardation layer, and that imparts a phase difference of ½ wavelength to transmitted light;
A quarter-wave retardation layer that is formed of a liquid crystal material that is oriented by the orientation-regulating force of the orientation film for the quarter-wave retardation layer and that imparts a quarter-wave phase difference to transmitted light; and a positive C plate layer And a laminate with
The positive C plate layer and the ½ wavelength retardation layer are bonded together by an adhesive layer, and the ½ wavelength retardation layer, the positive C plate layer, and the ¼ wavelength from the linearly polarizing plate side. An optical film provided with a retardation layer. The optical film according to claim 1, wherein an antireflection coating layer and / or a hard coating layer is provided on a side surface opposite to the quarter-wave plate of the linear polarizing plate.   The image display apparatus which has arrange | positioned the optical film of Claim 1 or Claim 2 on the image display panel surface by the adhesion layer. A transfer body for an optical film comprising a support substrate and a transfer layer,
The transfer layer is from the support substrate side,
The 1/4 wavelength phase difference layer formed of a liquid crystal material aligned by the alignment regulating force of the 1/4 wavelength phase difference layer alignment layer, and imparting a phase difference of 1/4 wavelength to transmitted light;
A positive C plate layer;
An adhesive layer with an adhesive;
A ½ wavelength retardation layer that is formed of a liquid crystal material that is aligned by the alignment regulating force of the alignment film for the ½ wavelength retardation layer and that sequentially imparts a ½ wavelength phase difference to the transmitted light is sequentially provided. And
The transfer body for optical films, in which the ½ wavelength retardation layer, the positive C plate layer and the ¼ wavelength retardation layer are laminated together by the adhesive layer. The transfer layer is
The optical film transfer body according to claim 4, wherein the ½ wavelength retardation layer alignment film is provided on a side surface opposite to the adhesive layer of the ½ wavelength retardation layer. The transfer layer is
6. The optical film transfer body according to claim 4, wherein the quarter-wave retardation layer alignment film is provided on a side surface of the quarter-wave retardation layer opposite to the adhesive layer. An optical film transfer body producing step for producing an optical film transfer body;
A bonding step according to a linearly polarizing plate, wherein the optical film transfer body is bonded to a linearly polarizing plate to produce a laminate of the optical film transfer body and the linearly polarizing plate;
A support substrate peeling step in which the support substrate of the optical film transfer member is peeled from the laminate of the optical film transfer member and the linearly polarizing plate, and the adhesive layer and the separator film are sequentially disposed,
The transfer film production process for the optical film,
An alignment film for a quarter-wave retardation layer related to a quarter-wave retardation layer on the support substrate, and a liquid crystal material aligned by an alignment regulating force of the alignment film for the quarter-wave retardation layer The quarter-wave retardation layer and the positive C-plate layer are sequentially formed to provide a quarter-wave phase difference to the transmitted light to produce a laminate on the quarter-wave retardation layer side. Producing a quarter-wave retardation layer,
By the alignment regulating force of the alignment film for 1/2 wavelength retardation layer and the alignment film for 1/2 wavelength retardation layer related to the 1/2 wavelength retardation layer on the substrate on the 1/2 wavelength retardation layer side A layered body on the ½ wavelength phase difference layer side is prepared by sequentially producing the ½ wavelength phase difference layer formed of an aligned liquid crystal material and imparting a phase difference of ½ wavelength to transmitted light. A step of producing a half-wave retardation layer;
A method for producing an optical film, comprising: a step of laminating the half-wave retardation layer and a positive C plate layer with an adhesive layer to produce the optical film transfer body. Formed on a support base material by an alignment film for a quarter wavelength retardation layer according to a quarter wavelength retardation layer, and a liquid crystal material aligned by the alignment regulating force of the alignment film for a quarter wavelength retardation layer The quarter-wave retardation layer for imparting a quarter-wave phase difference to the transmitted light and the positive C plate layer are sequentially produced to produce a laminate on the quarter-wave retardation layer side. A step of producing a quarter-wave retardation layer;
An alignment film for a 1/2 wavelength retardation layer according to a 1/2 wavelength retardation layer on the substrate on the 1/2 wavelength retardation layer side, and an alignment regulating force of the alignment film for the 1/2 wavelength retardation layer A layered body on the ½ wavelength phase difference layer side is prepared by sequentially producing the ½ wavelength phase difference layer, which is formed of a liquid crystal material aligned by the above, and imparts a phase difference of ½ wavelength to transmitted light. A step of producing a ½ wavelength retardation layer,
A bonding step according to a quarter-wave plate for producing a quarter-wave plate by bonding the half-wave retardation layer and the positive C plate layer with an adhesive layer;
From the quarter-wave plate, the base material on the half-wavelength retardation layer side, or the laminate of the base material on the half-wavelength retardation layer side and the alignment film for the half-wavelength retardation layer The manufacturing method of the transcription | transfer body for optical films provided with the peeling process which peels and produces the transcription | transfer body for optical films.

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