JP4086197B2 - Optical film manufacturing equipment - Google Patents

Description

  The present invention relates to an apparatus for producing an optical film formed by at least dyeing, crosslinking and stretching a film made of a hydrophilic polymer.

  Liquid crystal display devices using optical films are used in various applications such as televisions and personal computers. In recent years, liquid crystal display devices and the like have been increased in size, so that an optical film having a large area is required, and along with the increase in area, an optical film manufacturing facility has also been increased in size.

  In general, the optical film is produced by at least dyeing, crosslinking, and stretching a long film made of a hydrophilic polymer. For example, the following Patent Document 1 discloses the production of a polarizing film in which a film formed from a mixture containing a hydrophilic polymer and a dichroic dye is uniaxially stretched and then treated with an aqueous solution containing boric acid. A method is disclosed. In Patent Document 1, it is also disclosed that when a film is treated with an aqueous boric acid solution, for example, it is performed at a temperature of 55 ° C. or higher.

  However, if the film is dipped in a relaxed state in a bath having a bath temperature of 50 ° C. or higher, the film may be excessively swollen and softened. In such a case, when the film is stretched at a high magnification of 5 times or more, there is a problem that the film is easily broken from the softened portion. In particular, in a large-sized bath, the operation of passing a long film between guide rolls increases the immersion time of the film, so that the film is swelled and softened easily, and the film is easily broken.

  Further, the operation of passing a long film through a guide roll in a bath is generally performed by putting a hand directly in the bath and performing a manual operation for a long time or using a guide string. Therefore, there is also a problem that workability and production efficiency are inferior.

Japanese Patent Publication No.7-46162

The present invention has been made to solve the above problems, and can be used for a method for producing an optical film that can be stretched without breaking a film including a hydrophilic polymer and can improve throughput. An object of the present invention is to provide an optical film manufacturing apparatus capable of improving workability and production efficiency.

  The inventor of the present application intensively studied an apparatus for producing an optical film in order to solve the conventional problems. As a result, the inventors have found that the object can be achieved by adopting the following configuration, and have completed the present invention.

  In order to solve the above problems, an optical film manufacturing apparatus according to the present invention transports the film in a predetermined direction in an optical film manufacturing apparatus using a film including a hydrophilic polymer. A pair of transport rolls, one or more support members that are positioned between the pair of transport rolls and support the film from below when the film is passed between the transport rolls, and the film in the solution A pressing member positioned between the bath for dipping and the pair of transport rolls, and when the film is immersed in the solution, the film is pressed down and immersed in a stretched state without being loosened. It is characterized by having.

  According to the above configuration, since the film is not immersed in the solution in a relaxed state, the film can be prevented from being excessively swollen and softened. Moreover, immersion of a film can be simply performed by moving the support member and pressing member of the state which supported the film below. This eliminates the need for manual work such as passing the film between the transport rolls in the bath and the use of a guide string, and improves workability and production efficiency. The film can also be uniformly immersed in the solution. Further, since the pressing member is immersed while pressing the film, the film is convex downward toward the solution. As a result, the film can be surely immersed without causing air accumulation.

  It is preferable that the pair of transport rolls stretch a film immersed in the solution without being slackened by a difference in peripheral speed.

  According to the above configuration, the film is stretched by the difference in peripheral speed between the pair of transport rolls while suppressing excessive swelling and softening of the film, so that it is excellent in heat resistance and water resistance without breaking. Enables the production of optical films.

  A guide member for adjusting the pass line of the film is provided between the pair of transport rolls, and the adjustment of the pass line is performed by moving the guide member into the bath. It can be performed by positioning at a different height from at least one of the pressing members.

  According to the above configuration, the guide member is positioned at a height different from that of at least one of the supporting member and the pushing member in the bath, so that the pass line and the process distance of the film immersed in the solution can be freely set. It becomes possible to adjust.

  It is preferable that the surface of the support member, the pressing member, or the guide member that contacts the film has a curved surface.

  According to the said structure, the resistance between a film and a supporting member, a pressing member, or a guide member can be reduced, and a film can be conveyed smoothly.

The present invention has the following effects by the means described above.
In other words, the optical film manufacturing apparatus according to the present invention eliminates the need for manual operations such as passing the film through a guide roll in a bath and the use of a guide string, which improves workability and production efficiency. I can plan.

  Embodiments of the present invention will be described below with reference to the drawings. However, parts that are not necessary for the description are omitted, and some parts are illustrated by being enlarged or reduced for easy explanation.

(Optical film manufacturing method)
First, the manufacturing method of an optical film is demonstrated taking a polarizing plate as an example. The manufacturing method of the optical film which concerns on this Embodiment is a protective film, such as a triacetyl cellulose, on the double-sided or single side | surface of the polarizer manufactured through the dyeing process of a long film, a bridge | crosslinking process, an extending process, a drying process, etc. A polarizing plate is formed by bonding.

  The film is not particularly limited. For example, a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, a polyethylene terephthalate film, an ethylene vinyl acetate copolymer film, a partially saponified film thereof, and a cellulose film. Examples of the polymer film such as a film include a dehydrated polyvinyl alcohol product and a polyethylene oriented film such as a dehydrochlorination treatment of polyvinyl chloride. In particular, a polyvinyl alcohol film is generally used because of the good orientation of iodine or a dichroic dye in the dyeing step described later.

  As a material for the polyvinyl alcohol film, polyvinyl alcohol (for example, VF-9P75RS made by Kuraray) or a derivative thereof is used. Derivatives of polyvinyl alcohol include polyvinyl formal, polyvinyl acetal and the like, olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, alkyl esters thereof, acrylamide and the like Can be given. Polyvinyl alcohol having a polymerization degree of about 2000 to 10,000, preferably having a polymerization degree of 2000 to 5000 and a saponification degree of about 80 to 100 mol% is generally used.

  The polyvinyl alcohol film may contain additives such as a plasticizer. Examples of the plasticizer include polyols and condensates thereof, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol. The amount of the plasticizer used is not particularly limited, but is preferably 20% by weight or less in the polyvinyl alcohol resin film.

  The dyeing step is a step of adsorbing and orienting the dichroic material on an unstretched or stretched film. In this step, for example, a method in which an unstretched film is stretched in water or pure water and then the stretched film is immersed in a bath containing a dyeing solution, or an unstretched film is bathed in a dyeing solution. It is possible to employ a method of stretching after being immersed in a film, or a method of stretching an unstretched film in a bath containing a dyeing solution. In each of these methods, the draw ratio is preferably about 1.5 to 3 times. Moreover, when using an unstretched film, the thickness of a film is about 50-110 micrometers. Furthermore, about 20-70 micrometers is suitable for the thickness of the film after extending | stretching. The stretching may be performed in multiple stages.

  As the dichroic material, iodine or a dichroic dye is used. Among these, when iodine is used, an iodine aqueous solution is generally used as the staining solution. As the aqueous iodine solution, in addition to iodine, an aqueous solution containing iodine ions with, for example, potassium iodide or the like is used. The iodine concentration is about 0.01 to 0.5% by weight, preferably 0.02 to 0.4% by weight, and the potassium iodide concentration is about 0.01 to 10% by weight, and further 0.02 to 8% by weight. % Is preferably used.

  In the iodine dyeing treatment, the temperature of the iodine solution is usually about 20 to 50 ° C, preferably 25 to 40 ° C. The immersion time is usually about 10 to 300 seconds, preferably 20 to 240 seconds.

  Examples of the dichroic dye include azo dyes, perylene dyes, and anthraquinone dyes. These dyes can be used as mixed dyes. These dyes are detailed in, for example, JP-A-54-76171.

  The crosslinking step is performed by immersing the film in a solution containing boric acid or borax. This process can improve the durability and stability of the long film by performing it once or a plurality of times together with the stretching process.

  In the present embodiment, the case where the crosslinking step is performed in two steps will be described as an example. If the cross-linking step is divided into two times, the dyed film can be cross-linked to some extent in the first cross-linking step, necking during stretching can be suppressed as much as possible, and a wide polarizer with a high degree of polarization can be produced. it can.

  The first crosslinking step is performed by immersing in a solution containing a crosslinking agent. Thereby, a certain amount of bridge | crosslinking can be given to a film. The treatment temperature in the first crosslinking step is preferably 20 to 50 ° C from the viewpoint of the degree of crosslinking, and more preferably 25 to 45 ° C. The treatment time is usually about 10 to 300 seconds, preferably about 20 to 240 seconds.

  The second crosslinking step is performed by immersing the film in a solution containing a crosslinking agent at a higher processing temperature than the first crosslinking step. At this time, the film is immersed in a state in which the film is stretched without slack. Thereby, it can prevent that a film swells excessively (for example, swelling more than about 3 times the initial state of a film), and softens too much. In order to keep the film stretched without slack, for example, a tensile force may be applied to the film in the longitudinal direction. The tensile force can be appropriately set depending on the film material, temperature, stretch ratio, and the like.

  The treatment temperature in the second crosslinking step is preferably 50 to 80 ° C, more preferably 55 to 70 ° C, from the viewpoint of improving the degree of polarization. When processing temperature is less than 50 degreeC, a film may not have sufficient transmittance | permeability and polarization degree. In addition, since the film does not swell sufficiently, it may be easily broken when stretched at a high magnification of 5 times or more. On the other hand, when the processing temperature exceeds 80 ° C., the film may swell and dissolve excessively and may be stretched and broken. The treatment time is usually about 10 to 800 seconds, preferably about 30 to 500 seconds. The treatment temperature of the second crosslinking step is not particularly limited as long as it is higher than the treatment temperature of the first crosslinking step, but is preferably 10 ° C or higher, more preferably 20 ° C or higher than the treatment temperature of the first crosslinking step. .

  In the second crosslinking step, a film stretching process is also performed. In this case, the stretching ratio is preferably about 5 to 7 times that of the initial state, and more preferably about 5.5 to 6.5 times that of the initial state. The film is gradually stretched in all steps such as the dyeing step, the first cross-linking step, the second cross-linking step, and when the total draw ratio is less than 5 times, a sufficient degree of polarization may not be obtained. . On the other hand, when the total draw ratio exceeds 7 times, breakage due to drawing tends to occur.

  A conventionally well-known thing can be used as said crosslinking agent, For example, boron compounds, such as a boric acid, borax, a glyoxal, glutaraldehyde, etc. can be illustrated. These may be one kind or two or more kinds may be used in combination. As the solution containing the crosslinking agent, an aqueous solution in which the crosslinking agent is dissolved in a solvent can be used. As the solvent, for example, water can be used. Further, it may contain an organic solvent compatible with water.

  The concentration of the crosslinking agent in the crosslinking solution used in the first and second crosslinking steps is not particularly limited, but is usually in the range of 2 to 10% by mass with respect to 100% by mass of the solvent (for example, water). Is preferred. When the crosslinking agent is boric acid, the boric acid concentration is preferably adjusted to 30% or more, more preferably 40% or more of the boric acid saturated dissolution concentration at each treatment temperature. For example, when the treatment temperature of the boric acid aqueous solution is 70 ° C., the boric acid saturated dissolution concentration of the boric acid aqueous solution is 13%, so that the boric acid concentration of the boric acid aqueous solution is 30%, 3.9% It is preferable to adjust so that it may become higher. Adjusting the boric acid concentration of the boric acid aqueous solution to the above range is advantageous in that the degree of swelling of the film can be adjusted. In particular, it is preferable that the boric acid concentration in the second crosslinking step is set higher than that in the first crosslinking step because the temperature of the second crosslinking step can be increased.

  An aqueous solution of boric acid or the like can contain iodine ions with potassium iodide. A boric acid aqueous solution or the like containing potassium iodide can obtain a lightly colored polarizer, that is, a so-called neutral gray polarizer having a substantially constant absorbance over almost the entire wavelength range of visible light.

  After the second crosslinking step, the film can be washed with pure water and dried according to a conventional method. Further, iodine ion impregnation treatment may be performed. Thereby, precipitation of boric acid etc. is prevented and a polarizer with a good appearance can be obtained. For the iodine ion impregnation treatment, for example, an aqueous solution containing iodine ions with potassium iodide or the like is used. The potassium iodide concentration is preferably about 0.5 to 10% by weight, more preferably 1 to 8% by weight. In the iodine ion impregnation treatment, the temperature of the aqueous solution is usually about 15 to 60 ° C, preferably 25 to 40 ° C. The immersion time is usually about 1 to 120 seconds, preferably 3 to 90 seconds.

  As described above, according to the method of manufacturing an optical film according to the present embodiment, since the film 1 is not immersed in the solution in a slack state, the film 1 is prevented from being excessively swollen and softened. As a result, a polarizer can be produced without breaking when the film 1 is stretched.

  In the present invention, in addition to the second cross-linking step, when the film is immersed in each step such as the dyeing step and the first cross-linking step, the film may be stretched without slack. Good. Moreover, it is not necessary to perform each process, such as dyeing | staining, bridge | crosslinking, and extending | stretching separately, and you may perform simultaneously. Moreover, the order of each process is not specifically limited. Furthermore, in addition to the crosslinking step, the stretching step may be performed twice or more.

(Optical film manufacturing equipment)
The optical film manufacturing apparatus according to the present embodiment will be described. FIG. 1 is an explanatory view schematically showing an optical film manufacturing apparatus, in which FIG. 1 (a) shows a state where the film is stretched, FIG. 1 (b) shows an initial stage of film immersion, FIG. 2C shows a state where the film is immersed and stretched.

  As shown to Fig.1 (a), the manufacturing apparatus of the optical film which concerns on this Embodiment is the exit side conveyance roll 2, the inlet side conveyance roll 3, the bath 4, the support member 5, and the guide member 6. And a pushing member 7.

  The exit side transport roll 2 and the entrance side transport roll 3 transport the film 1 in the direction of the arrow shown in FIG. At this time, the film 1 is applied with a tensile force in a direction parallel to the transport direction, and is maintained in a stretched state without slack.

  The bath 4 is a large bathtub of 10 m or more with respect to the conveying direction of the long film 1. The bath 4 is filled with a solution 8 containing a dichroic material or a crosslinking agent.

  The support member 5 supports the film 1 on the bath 4 from below. The support member 5 has a roll shape that is rotatably supported. Further, as shown in FIGS. 1 (b) and 1 (c), the support member 5 is movable in the vertical direction, so that the support member 5 is not hindered when the film 1 is immersed in the bath 4. ing.

  The guide members 6 are provided on both sides of the support member 5 and are disposed so as to be positioned on the upper side of the film 1 spanned between the outlet-side transport roll 2 and the inlet-side transport roll 3. The guide member 6 has a rotatable roll shape. Further, the guide member 6 can be moved in the vertical direction as shown in FIGS. 1B and 1C, so that the pass line and the process distance in the bath 4 of the film 1 can be adjusted. It has become.

  The pushing member 7 is provided at a position facing the support member 5 with the film 1 interposed therebetween. The pushing member 7 has a roll shape that is rotatably supported. Further, as shown in FIG. 1 (b), the pressing member 7 can move in the vertical direction, whereby the film 1 can be pressed when the film 1 is immersed in the bath 4.

  The method for moving the support member 5, the guide member 6 or the pushing member 7 in the vertical direction is not particularly limited, and a conventionally known method can be employed. Specifically, for example, a jack-up system, a hydraulic system, etc. can be exemplified. Moreover, the support member 5, the guide member 6, and the pressing member 7 are not limited to the said roll-shaped thing, For example, a non-rotation fixed type may be sufficient. Furthermore, the shape of the support member 5, the guide member 6, and the pressing member 7 is not specifically limited, The surface which contacts the film 1 should just be a curved surface at least. Therefore, for example, it is also possible to have a shape such as a semicircular cross section, an ellipse, or a sector. By adopting these shapes, the frictional resistance on the contact surface between the film 1 and the support member 5, the guide member 6 or the pressing member 7 is reduced, and the film 1 can be smoothly conveyed.

  Next, operation | movement of the manufacturing apparatus of the optical film which concerns on this Embodiment is demonstrated. First, as shown in FIG. 1A, the film 1 is stretched between the outlet-side transport roll 2 and the inlet-side transport roll 3. At this time, the film 1 is supported by the support member 5 located outside the bath 4 and is stretched without slack. The film 1 is not immersed in the solution 8 of the bath 4.

  Subsequently, as shown in FIG. 1B, the pressing member 7 moves downward to the inside of the bath 4 while pressing the film 1 in a state in which the pressing member 7 is stretched without slack. Thereby, the film 1 is immersed in the solution 8. At this time, the support member 5 also moves downward to the inside of the bath 4. Since the film 1 is pressed down so as to have a convex shape, no air pocket is formed on the lower side of the film 1 when immersed in the solution 8. As a result, the film 1 can be surely immersed in the solution 8.

  Furthermore, after the leading edge of the film 1 that has a convex shape starts to be immersed in the solution 8, the guide member 6 is lowered at a speed equal to or lower than the lowering speed of the pressing member 7. The guide members 6 are lowered until they are positioned further below the support member 5. The two guide members 6 are at the same height position. As a result, the support member 5 and the guide member 6 are positioned so as to be relatively different in the vertical direction in the bath 4. Thus, the film 1 can form a pass line that is alternately bent in the vertical direction with the support member 5 and the guide member 6 as fulcrums, and can be immersed for a long time. In addition, the film 1 can be immersed in the bath 4 as widely as possible.

  In addition, the immersion of the film 1 is performed by moving the support member 5 further downward than the guide member 6 and pushing in after the tip of the film 1 having a convex shape on the lower side starts to be immersed in the solution 8. By positioning the member 7 above the guide member 6, the pass line of the film 1 may not be bent in the vertical direction in the bath 4 (see FIG. 2A). 2B, the support member 5 and the pushing member 7 are moved below the guide member 6 so that the pass line of the film 1 is guided by the guide member 6 and the pushing member 7 in the bath 4. You may make it.

  After the immersion, the film 1 is stretched by 5 to 7 times the initial state due to the peripheral speed difference between the exit side transport roll 2 and the entrance side transport roll 3.

  As described above, according to the optical film manufacturing apparatus of the present embodiment, the film 1 is dipped in the bath 4 after the film 1 is preliminarily spread over the outlet-side transport roll 2 and the inlet-side transport roll 3. In this case, the manual work such as passing the film 1 through the guide member 6 and the like, and the use of a guide string are not required. Moreover, since the film 1 can be immersed only by lowering the support member 5, the guide member 6, and the pressing member 7, workability and production efficiency can be improved. Further, the optical film manufacturing apparatus according to the present embodiment can be used in each process such as dyeing and crosslinking.

  In the optical film manufacturing apparatus, the case where one support member 5 is provided has been described. However, the present invention is not limited to such a configuration, and a plurality of support members are provided. The provided structure may be sufficient. For example, an optical film manufacturing apparatus provided with two support members 5 will be described as follows. FIG. 3 is an explanatory view schematically showing another optical film manufacturing apparatus according to the present embodiment, in which FIG. 3 (a) shows a state where the film is stretched, and FIG. c) shows the process of extending | stretching a film. FIGS. 4A and 4B also show other processes for stretching the film.

  First, as shown in FIG. 3A, the film 1 is stretched between the outlet-side transport roll 2 and the inlet-side transport roll 3. At this time, the film 1 is supported by the two support members 5 located outside the bath 4. The film 1 is immersed in such a manner that the film 1 is projected downward by being lowered to the inside of the bath 4 while pressing the film 1 in a state where the pressing member 7 is stretched without slack. At this time, the two support members 5 are also lowered.

  For example, as shown in FIG. 3B, the immersion of the film 1 is such that the two support members 5 are positioned relatively higher than the guide member 6 and the pressing member 7, and the guide member 6 and the pressing member 7. Are located at the same height. Thereby, the film 1 can form a pass line that is alternately bent in the vertical direction with the support member 5, the guide member 6, and the pressing member 7 as fulcrums, and can be immersed for a long time.

  Further, as shown in FIG. 3C, the two guide members 6 are positioned so as to be horizontal between the lowermost support member 5 and the uppermost push-in member 7, so that the guide member 6 It may be soaked and stretched so that the film 1 bends with fulcrum as a fulcrum. Further, as shown in FIG. 4A, the pushing member 7 is positioned between the lowermost support member 5 and the uppermost guide member 6, and the guide member 6 and the pushing member 7 are used as fulcrums. Immersion and stretching may be performed so that the film 1 is bent. Further, as shown in FIG. 4B, the support member 5 is positioned in the middle between the lowermost guide member 6 and the uppermost push-in member 7, and the support member 5 and the guide member 6 are used as fulcrums. Immersion and stretching may be performed so that the film 1 is bent.

(Optical film and image display device)
The polarizer (optical film) obtained by the production method can be a polarizing plate provided with a transparent protective layer on at least one surface thereof according to a conventional method. The transparent protective layer can be provided as a polymer-coated layer or a film laminate layer. As the transparent polymer or film material for forming the transparent protective layer, an appropriate transparent material can be used, but a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property and the like is preferably used. Examples of the material for forming the transparent protective layer include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as cellulose diacetate and cellulose triacetate, acrylic polymers such as polymethyl methacrylate, polystyrene, acrylonitrile, Examples thereof include styrene polymers such as styrene copolymers (AS resins), polycarbonate polymers, and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of the polymer that forms the transparent protective layer.

  The surface of the transparent protective film to which the polarizer is not adhered (the surface on which the coating layer is not provided) has been subjected to a hard coat layer, antireflection treatment, antisticking, or treatment for diffusion or antiglare. Also good.

  The hard coat treatment is applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone is used. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

  The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a blending method of transparent fine particles. The fine particles to be included in the formation of the surface fine concavo-convex structure are, for example, conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like having an average particle size of 0.5 to 50 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles composed of a crosslinked or uncrosslinked polymer, and the like are used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, antisticking layer, diffusing layer, antiglare layer and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective layer as an optical layer.

  An adhesive is used for the adhesion treatment between the polarizer and the transparent protective film. Examples of the adhesive include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latexes, and water-based polyesters. The said adhesive agent is normally used as an adhesive agent which consists of aqueous solution, and contains 0.5 to 60 weight% of solid content normally.

  The polarizing plate is produced by bonding the transparent protective film and a polarizer using the adhesive. The adhesive may be applied to either the transparent protective film or the polarizer, or to both. After the bonding, a drying process is performed to form an adhesive layer composed of a coating dry layer. Bonding of a polarizer and a transparent protective film can be performed by a roll laminator or the like. The thickness of the adhesive layer is not particularly limited, but is usually about 0.05 to 5 μm.

  The optical film of the present invention can also be used as an optical film laminated with another optical layer in practical use for a polarizing plate. The optical layer is not particularly limited. For example, for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), and a viewing angle compensation film. One or more optical layers that may be used can be used. In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate or a semi-transmissive reflecting plate is further laminated on the polarizing plate of the present invention, an elliptical polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on the polarizing plate. A wide viewing angle polarizing plate obtained by further laminating a viewing angle compensation film on a plate or a polarizing plate, or a polarizing plate obtained by further laminating a brightness enhancement film on the polarizing plate is preferable.

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. Moreover, the transparent protective film contains fine particles so as to have a surface fine concavo-convex structure and a reflective layer having a fine concavo-convex structure thereon. The reflective layer having the fine concavo-convex structure has an advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance and to suppress unevenness in brightness and darkness. The transparent protective film containing fine particles also has an advantage that incident light and its reflected light are diffused when passing through it, and light and dark unevenness can be further suppressed. The reflective layer of the fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film is formed by transparent the metal by an appropriate method such as a vapor deposition method such as a vacuum vapor deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of directly attaching to the surface of the protective layer.

  Instead of the method of directly applying the reflecting plate to the transparent protective film of the polarizing plate, the reflecting plate can be used as a reflecting sheet provided with a reflecting layer on an appropriate film according to the transparent film. Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate or the like is used to prevent the reflectance from being lowered due to oxidation, and thus to maintain the initial reflectance for a long time. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device or the like that displays an image using a built-in light source such as a backlight built in the back side of the transflective polarizing plate can be formed. In other words, the transflective polarizing plate is useful for forming a liquid crystal display device of a type that can save energy of using a light source such as a backlight in a bright atmosphere and can be used with a built-in light source even in a relatively dark atmosphere. It is.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. A phase difference plate or the like is used when changing linearly polarized light to elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called quarter-wave plate (also referred to as a λ / 4 plate) is used as a retardation plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A half-wave plate (also referred to as a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function. Specific examples of the retardation plate include a birefringent film obtained by stretching a film made of an appropriate polymer such as polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene, other polyolefins, polyarylate, and polyamide. And an alignment film of a liquid crystal polymer, and a liquid crystal polymer alignment layer supported by a film. The retardation plate may have an appropriate retardation according to the purpose of use, such as those for the purpose of compensating for various wavelength plates or birefringence of the liquid crystal layer, viewing angle, and the like. What laminated | stacked the phase difference plate and controlled optical characteristics, such as phase difference, etc. may be used.

  The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially laminating them sequentially in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflective) polarizing plate and a retardation plate. An optical film such as a polarizing plate has an advantage that it can improve the production efficiency of a liquid crystal display device and the like because of excellent quality stability and lamination workability.

  The viewing angle compensation film is a film for widening the viewing angle so that an image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction rather than perpendicular to the screen. As such a viewing angle compensation phase difference plate, for example, a retardation film, an alignment film such as a liquid crystal polymer, or an alignment layer such as a liquid crystal polymer supported on a transparent substrate is used. A normal retardation plate uses a birefringent polymer film uniaxially stretched in the plane direction, whereas a retardation plate used as a viewing angle compensation film stretches biaxially in the plane direction. Birefringent polymer film, biaxially stretched film such as polymer with birefringence with a controlled refractive index in the thickness direction that is uniaxially stretched in the plane direction and stretched in the thickness direction, etc. Used. Examples of the inclined alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and shrinking the polymer film under the action of the contraction force by heating, and a film obtained by obliquely aligning a liquid crystal polymer. Can be mentioned. The raw material polymer for the phase difference plate is the same as the polymer described in the previous phase difference plate, preventing coloration due to a change in the viewing angle based on the phase difference by the liquid crystal cell and expanding the viewing angle for good visual recognition. An appropriate one for the purpose can be used.

  Also, from the viewpoint of achieving a wide viewing angle with good visibility, an optically compensated phase difference in which a liquid crystal polymer alignment layer, in particular an optically anisotropic layer composed of a discotic liquid crystal polymer gradient alignment layer, is supported by a triacetylcellulose film. A plate can be preferably used.

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer or the like provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. Luminance can be improved by increasing the amount of light transmitted through the improving film and increasing the amount of light that can be used for liquid crystal display by supplying polarized light that is difficult to absorb into the polarizer. That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and the amount of light that can be used for liquid crystal image display or the like is reduced accordingly, resulting in a dark image. The brightness enhancement film allows light having a polarization direction that is absorbed by the polarizer to be reflected once by the brightness enhancement film without being incident on the polarizer, and further inverted through a reflective layer provided on the rear side thereof. Repeatedly re-enter the brightness enhancement film, and the brightness enhancement film transmits only polarized light whose polarization direction is such that the polarization direction of light reflected and inverted between the two can pass through the polarizer. Therefore, light such as a backlight can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of dielectric material or a multilayer laminate of thin film films having different refractive index anisotropies. Such as an alignment film of a cholesteric liquid crystal polymer or an alignment liquid crystal layer supported on a film substrate, which reflects either left-handed or right-handed circularly polarized light and transmits other light. Appropriate things, such as a thing, can be used.

  Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis as described above, the transmitted light is incident on the polarizing plate with the polarization axis aligned as it is, thereby efficiently transmitting while suppressing absorption loss due to the polarizing plate. Can be made. On the other hand, in a brightness enhancement film of a type that emits circularly polarized light such as a cholesteric liquid crystal layer, it can be incident on a polarizer as it is, but from the viewpoint of suppressing absorption loss, the circularly polarized light is linearly polarized through a retardation plate. It is preferable to make it enter into a polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region exhibits, for example, a retardation layer that functions as a quarter-wave plate for light-color light having a wavelength of 550 nm and other retardation characteristics. It can be obtained by a method of superposing a retardation layer, for example, a retardation layer functioning as a half-wave plate. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.

  In addition, the cholesteric liquid crystal layer can also be obtained by reflecting circularly polarized light in a wide wavelength range such as a visible light region by combining two or more layers having different reflection wavelengths and having an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Further, the polarizing plate may be formed by laminating a polarizing plate and two or three or more optical layers like the above-described polarization separation type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-mentioned reflective polarizing plate or semi-transmissive polarizing plate and a retardation plate are combined may be used.

  An optical film in which the optical layer is laminated on a polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of a liquid crystal display device or the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate and other optical films, their optical axes can be set at an appropriate arrangement angle in accordance with the target retardation characteristics.

  An adhesive layer for adhering to other members such as a liquid crystal cell may be provided on the polarizing plate described above or an optical film in which at least one polarizing plate is laminated. The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited. For example, an acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer is appropriately selected. Can be used. In particular, those having excellent optical transparency such as an acrylic pressure-sensitive adhesive, exhibiting appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and being excellent in weather resistance, heat resistance and the like can be preferably used.

  In addition to the above, in terms of prevention of foaming and peeling phenomena due to moisture absorption, deterioration of optical properties and liquid crystal cell warpage due to differences in thermal expansion, etc., as well as formability of liquid crystal display devices with high quality and excellent durability An adhesive layer having a low moisture absorption rate and excellent heat resistance is preferred.

  The adhesive layer is, for example, natural or synthetic resins, in particular, tackifier resins, fillers or pigments made of glass fibers, glass beads, metal powders, other inorganic powders, colorants, antioxidants, etc. It may contain an additive to be added to the adhesive layer. Moreover, the adhesion layer etc. which contain microparticles | fine-particles and show light diffusibility may be sufficient.

  Attachment of the adhesive layer to one or both sides of the polarizing plate or the optical film can be performed by an appropriate method. For example, a pressure sensitive adhesive solution of about 10 to 40% by weight in which a base polymer or a composition thereof is dissolved or dispersed in a solvent composed of a suitable solvent alone or a mixture such as toluene and ethyl acetate is prepared. A method in which it is directly attached on a polarizing plate or an optical film by an appropriate development method such as a casting method or a coating method, or an adhesive layer is formed on a separator according to the above, and this is applied to a polarizing plate or an optical film. The method of moving up is mentioned.

  The pressure-sensitive adhesive layer can be provided on one side or both sides of a polarizing plate or an optical film as a superimposed layer of different compositions or types. Moreover, when providing in both surfaces, it can also be set as the adhesion layers of a different composition, a kind, thickness, etc. in the front and back of a polarizing plate or an optical film. The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to the purpose of use and adhesive force, and is generally 1 to 500 μm, preferably 5 to 200 μm, particularly preferably 10 to 100 μm.

  On the exposed surface of the adhesive layer, a separator is temporarily attached and covered for the purpose of preventing contamination until it is put to practical use. Thereby, it can prevent contacting an adhesion layer in the usual handling state. As the separator, except for the above thickness conditions, for example, a suitable thin leaf body such as a plastic film, rubber sheet, paper, cloth, non-woven fabric, net, foam sheet, metal foil, laminate thereof, and the like, silicone type or Appropriate conventional ones such as those coated with an appropriate release agent such as long-chain alkyl, fluorine-based, or molybdenum sulfide can be used.

  In the present invention, the polarizer, transparent protective film, optical film, and the like that form the polarizing plate described above, and each layer such as an adhesive layer include, for example, salicylic acid ester compounds, benzophenol compounds, benzotriazole compounds, and cyanoacrylates. It may be a compound having an ultraviolet absorbing ability by a method such as a method of treating with an ultraviolet absorber such as a compound based on nickel or a nickel complex salt compound.

  The polarizing plate or the optical film of the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, a polarizing plate or an optical film, and an illumination system as necessary, and incorporating a drive circuit. There is no limitation in particular except the point which uses the polarizing plate or optical film by invention, and it can apply according to the former. As the liquid crystal cell, any type such as a TN type, an STN type, or a π type can be used.

  An appropriate liquid crystal display device such as a liquid crystal display device in which a polarizing plate or an optical film is disposed on one side or both sides of a liquid crystal cell, or a backlight or a reflector used in an illumination system can be formed. In that case, the polarizing plate or optical film by this invention can be installed in the one side or both sides of a liquid crystal cell. When providing a polarizing plate or an optical film on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light emitting layer, and electron injection layer is known. It has been.

  In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the phosphor material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

  Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .

  That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light particularly when the phase difference plate is a quarter wavelength plate and the angle between the polarization direction of the polarizing plate and the phase difference plate is π / 4. .

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

  Hereinafter, preferred embodiments of the present invention will be described in detail by way of example. However, the materials, blending amounts, and the like described in the examples are not intended to limit the scope of the present invention only to them, but are merely illustrative examples, unless otherwise specified.

Example 1
Using a polyvinyl alcohol film having a polymerization degree of 2400 and a thickness of 75 μm, a polarizer was produced through the steps of swelling, dyeing, first crosslinking, second crosslinking, stretching, washing, and drying. That is, the long film was immersed in water at 30 ° C., and further stretched to 3 times the initial state (swelling step).

  Next, a dyeing solution was prepared so that the transmittance of the polarizing plate as the final product was 43.5%. That is, after adding 2 wt% of potassium iodide to 30 ° C. water, a high-concentration iodine solution was further added to prepare a staining solution. The high-concentration iodine solution is a solution for adjusting the iodine concentration of a dyeing solution in which water: potassium iodide: iodine is dissolved at a ratio of 100: 20: 1. The film was immersed in this dyeing solution and further stretched up to 4 times the initial state (dyeing process).

  Subsequently, 4 wt% boric acid and 2 wt% potassium iodide were added to water at 30 ° C. to prepare a first crosslinking solution. The film was immersed in this first crosslinking solution and further stretched to 4.3 times the initial state (first crosslinking step).

  Furthermore, 4 wt% boric acid and 2 wt% potassium iodide were added to 50 ° C. water to prepare a second crosslinking solution. The film was immersed and stretched in this second cross-linking solution in a stretched state (second cross-linking step). In addition, in this process, it performed using the manufacturing apparatus of the optical film demonstrated in the said embodiment (refer FIG. 1). That is, in the same manner as shown in FIG. 1 (a), the film is stretched between the exit-side transport roll and the entrance-side transport roll so that the film is supported by the support member and stretched without slack. did. Subsequently, in the same manner as shown in FIG. 1 (b), the film in which the pressing member was stretched without slack was immersed in the second cross-linking solution while being pressed down in a convex shape. . Further, the guide roll was lowered at the same speed as the descending speed of the pressing member until the guide roll was positioned further below the support member. After the immersion, the film was stretched until it became 6 times the initial state due to the difference in peripheral speed between the exit side transport roll and the entrance side transport roll.

  The film after the second crosslinking step was immersed in a 4 wt% potassium iodide aqueous solution at 30 ° C. and further stretched to 6.05 times the initial state (cleaning step). Thereafter, the film was pulled up from a 4 wt% potassium iodide aqueous solution and dried at 30 ° C. for 2 minutes (drying step).

  Thereby, an optical film according to Example 1 was produced.

(Example 2)
In Example 2, the optical film according to Example 2 was prepared in the same manner as in Example 1 except that the temperature of the second crosslinking solution used in Example 1 was changed from 50 ° C. to 60 ° C. Produced.

(Example 3)
In Example 3, the boric acid concentration of the second crosslinking solution used in Example 1 was changed from 4 wt% to 8 wt%, and the temperature was changed from 50 ° C. to 70 ° C. In the same manner as in Example 1, an optical film according to Example 3 was produced.

Example 4
In Example 4, the boric acid concentration of the second crosslinking solution used in Example 1 was changed from 4 wt% to 10 wt%, and the temperature was changed from 50 ° C. to 80 ° C. Example 1 In the same manner as described above, an optical film according to Example 4 was produced.

(Comparative Example 1)
In the comparative example 1, in the second cross-linking step, when the long film is transferred between the transport rolls, the guide film in the bath is manually bathed in the state where the long film is immersed in the bath. Soaked through. About the others, it carried out similarly to Example 1, and produced the optical film which concerns on the comparative example 1. FIG.

(Comparative Example 2)
In this Comparative Example 2, the optical film according to this Comparative Example 2 was prepared in the same manner as in Comparative Example 1 except that the temperature of the second crosslinking solution used in Comparative Example 1 was changed from 50 ° C. to 60 ° C. Fabrication was performed.

(Comparative Example 3)
In Comparative Example 3, the boric acid concentration of the second crosslinking solution used in the second crosslinking step of Comparative Example 1 was changed from 4 wt% to 8 wt%, and the temperature was changed from 50 ° C. to 70 ° C. Produced the optical film which concerns on this comparative example 3 like the comparative example 1. FIG.

(Comparative Example 4)
In Comparative Example 4, the boric acid concentration of the second crosslinking solution used in the second crosslinking step of Comparative Example 1 was changed from 4 wt% to 10 wt%, and the temperature was changed from 50 ° C. to 80 ° C. Produced the optical film which concerns on this comparative example 4 like the comparative example 1. FIG.

(Evaluation)
The optical films produced in the examples and comparative examples were examined for the presence or absence of stretch breakage. That is, the optical film was produced 10 times, the number of times the optical film was broken was counted, and the breaking rate was calculated. The results are shown in Table 1 below.

  As is apparent from Table 1, when optical films were produced under the same temperature conditions, Examples 1 to 4 showed 0% or very low breaking rates. On the other hand, in Comparative Example 1, the fracture rate was 80%, and the yield was extremely low. Furthermore, about Comparative Examples 2-4, the breaking rate was 100% and the optical film was not able to be produced. Thereby, when it was the manufacturing method of the optical film which concerns on Examples 1-4, the remarkable fracture | rupture prevention effect was seen and it was confirmed that the improvement of productivity and a yield can be aimed at.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which represents roughly the manufacturing apparatus of the optical film which concerns on one Embodiment of this invention, Comprising: The figure (a) shows the state which spanned the film, The figure (b) is the initial stage of film immersion. (C) shows the state of dipping and stretching the film. It is explanatory drawing which represents the manufacturing apparatus of the said optical film roughly, Comprising: The same figure (a) and (b) is explanatory drawing which shows the other example of immersion and extending | stretching of a film. It is explanatory drawing which shows schematically the manufacturing apparatus of the other optical film which concerns on other embodiment of this invention, Comprising: The same figure (a) shows the state over which the film was spanned, (b) and ( c) shows the process of extending | stretching a film. It is explanatory drawing which shows the manufacturing apparatus of the said optical film roughly, Comprising: The same figure (a) and (b) shows the other process of extending | stretching a film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film 2 Outlet side conveyance roll 3 Inlet side conveyance roll 4 Bath 5 Support member 6 Guide member 7 Push-in member 8 Solution

Claims (4)

In an optical film manufacturing apparatus using a film comprising a hydrophilic polymer,
A pair of transport rolls for transporting the film in a predetermined direction;
One or two or more support members that are located between the pair of transport rolls and support the film from below when the film is spanned between the transport rolls;
A bath for immersing the film in solution;
A pressing member positioned between the pair of transport rolls, the pressing member pressing down the film when the film is immersed in a solution, and a pressing member that immerses the film in a stretched state without slack. Optical film manufacturing equipment. 2. The optical film manufacturing apparatus according to claim 1 , wherein the pair of transport rolls stretches the film immersed in the solution without being slackened by a difference in peripheral speed. Between the pair of transport rolls, a guide member for adjusting the pass line of the film is provided,
Adjustment of the pass line, wherein the guide member is moved into said bath, claim and performs by positioning at least one different heights of the support member or pushing member in a bath 1 Or the manufacturing apparatus of the optical film of 2 . The optical film manufacturing apparatus according to any one of claims 1 to 3 , wherein a surface of the support member, the pressing member, or the guide member that contacts the long film has a curved surface.

Images