JP4399762B2 - Manufacturing method of long broadband 1/2 wavelength plate - Google Patents

Description

[0001]
  The present invention relates to an elongated broadband half-wave plateManufacturing methodMore specifically, it can be efficiently manufactured without adopting a so-called batch sticking process, and the ratio of the retardation value Re to the wavelength λ (Re / λ) is uniform over a wide band. Long broadband half-wave plate with high rateManufacturing methodAbout.
[0002]
[Prior art]
A liquid crystal display device such as a liquid crystal projector or a liquid crystal display uses a wave plate that has a small change in Re / λ with a change in wavelength and can give a predetermined phase difference over a wide wavelength range. So far, as such a wave plate, “laminated wave plate formed by laminating a plurality of stretched films that give a half-wave phase difference to monochromatic light with their optical axes crossed” (for example, Patent Document 1) and “a plurality of stretched films that give a half-wave phase difference with respect to monochromatic light are laminated with their optical axes crossed, and the birefringence difference of the stretched film There is a laminated wave plate characterized in that Δn1 / Δn2 <1.05 based on wavelength light of Δn1 and Δn2 based on wavelength light of 400 nm (Δn1) and 550 nm (Δn2) ”(Patent Document 2).
[0003]
[Patent Document 1]
JP-A-5-100114 (Claim 1)
[Patent Document 2]
JP-A-11-149015 (Claim 1)
In addition, there is also a “polarization axis rotating laminated retardation plate in which at least two retardation plates having a retardation value of 160 to 300 nm are laminated so that their slow axes are not parallel or orthogonal to each other”. It is known (see, for example, Patent Document 3).
[Patent Document 3]
JP-A-10-90521 (Claims 1 to 4)
[0004]
However, in any of the above publications, there is no clear description about the method for producing the wave plate, but in any case, for example, a rectangular retardation film is separated from the elongated stretched film obtained by the uniaxial stretching process. A plurality of rectangular stretched films having the same shape by cutting or punching the stretched film so that the stretch direction of the elongated stretched film differs from the rectangular axial direction. It is considered that the wave plate is manufactured by molding and then laminating a plurality of, for example, two stretched films with an adhesive or an adhesive. As described above, a method of manufacturing a wave plate by laminating a retardation film cut or punched from a stretched film is referred to as “batch sticking”.
[0005]
However, if the wave plate is manufactured as described above, the complicated work of pasting retardation films obtained by cutting or punching is repeated, and a plurality of retardation films are accurately pasted together. Exquisite work is required, and therefore production efficiency is remarkably poor. In particular, in a precise laminating operation for accurately laminating a plurality of retardation films, it is extremely difficult to produce a wave plate having a uniform retardation, and thus there is a problem that the yield is poor.
[0006]
[Problems to be solved by the invention]
  The present invention eliminates the above-mentioned conventional problems, can be manufactured efficiently, and is a long broadband half-wave plate having excellent phase difference uniformity.Manufacturing methodThe issue is to provide
[0007]
[Means for Solving the Problems]
  The first means for solving the problems of the present invention is as follows:
(1) A long broadband half-wave plate formed by laminating two long retardation films so that their longitudinal directions coincide.Manufacturing methodBecause,Stretched in the stretching direction with a stretching angle θ of 22.5 ± 2.5 degrees with respect to the width direction orthogonal to the longitudinal direction of the unstretched filmBy forming an obliquely stretched film that is the retardation filmA roll-to-roll method is used to laminate a take-up film obtained by winding up the obliquely stretched film and a reverse take-up film wound up in a reverse direction with respect to the take-up film so that the stretch directions intersect each other.DoElongated broadband half-wave plateManufacturing methodIt is.
[0008]
  As a preferable aspect in the first means, the long broadband half-wave plate of the following (2) to (6)Manufacturing methodCan be mentioned.
(2) In the obliquely stretched film, both ends in the width direction of the unstretched film are fed at the same linear velocity so that the moving distance at one end in the width direction of the unstretched film is larger than the moving distance at the other end. The long broadband half-wave plate according to (1), which is formed using an oblique stretching device that stretchesManufacturing method.
(3) Each of the retardation films has a retardation value Re (550) measured at a wavelength of 550 nm of 275 ± 10 nm, and the long broadband half-wave plate according to (1) or (2)Manufacturing method.
(4) The long broadband half-wave plate according to any one of (1) to (3), wherein the retardation film is a film formed of an alicyclic structure-containing polymer resin.Manufacturing method.
(5) The long stretched half-wave plate according to any one of (1) to (4), wherein the obliquely stretched film has a residual volatile component amount of at most 0.1% by mass.Manufacturing method.
(6) The long wideband half-wave plate according to any one of (1) to (5), wherein the long wideband half-wave plate is for a liquid crystal projector.Manufacturing method.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The long broadband half-wave plate of the present invention is formed by laminating a plurality of long retardation films, and the long retardation of at least one layer of the long retardation films. The film is formed by oblique stretching.
[0011]
Here, the broadband ½ wavelength plate is a retardation element having a ½ wavelength phase difference in a wide wavelength range of 450 to 650 nm, for example. The half-wave plate rotates the vibration surface by 90 ° when polarized light having a vibration surface that intersects the slow axis (the direction in which the refractive index becomes maximum in the plane) at an angle of 45 ° is passed. It has a function.
[0012]
FIG. 1 shows a cross section of the long broadband half-wave plate of the present invention. In FIG. 1, reference numeral 1 denotes a long broadband half-wave plate, and 2 denotes a retardation film constituting the same. Here, at least one of the retardation films 2-1 and 2-2 was obtained by oblique stretching, and both of these two retardation films were obtained by oblique stretching. It doesn't matter. When the long broadband half wave plate of the present invention is composed of two retardation films, the retardation films are laminated so that their slow axes intersect at 45 ± 5 °.
[0013]
FIG. 1 shows a long broadband 1/2 wavelength plate formed by laminating two retardation films, but the present invention is not limited to two, and the long broadband 1/2 The two-wavelength plate may be composed of three or more retardation films. When three or more retardation films are used, it is sufficient that at least one of the retardation films is obliquely stretched, and all of the retardation films may be obliquely stretched.
[0014]
Further, FIG. 1 shows only the long broadband half-wave plate of the present invention and the retardation film constituting the same, but actually, as shown in FIG. 2, the retardation film is an adhesive. It may be laminated via a layer or an adhesive layer 3. Examples of such adhesives or pressure-sensitive adhesives include acrylic, silicone-based, polyester-based, polyurethane-based, polyether-based, or synthetic rubber-based transparent adhesives or pressure-sensitive adhesives. The thickness of the adhesive layer or the pressure-sensitive adhesive layer 3 is usually in the range of 1 to 100 μm, preferably 1 to 30 μm.
[0015]
The retardation value Re (550) measured at a wavelength of 550 nm of the retardation film used in the present invention is preferably 275 ± 10 nm. The retardation value Re is the difference in refractive index Δn (n₁-N₂) × retardation film thickness D. n₁Is the refractive index in the slow axis direction of the retardation film, and n₂Is the refractive index in the fast axis direction of the retardation film. Where n₁> N₂It is. When the retardation value Re (550) is 275 ± 10 nm, when a retardation film is laminated, it functions as a better half-wave plate in a wide wavelength region including wavelengths of 450 to 650 nm. Because you can.
[0016]
The retardation film constituting the long broadband ½ wavelength plate of the present invention can be formed of a thermoplastic resin having good transparency. Examples of the thermoplastic resin include polyolefin resins, alicyclic structure-containing polymer resins, polycarbonate resins, polyester resins, polysulfone resins, polyether polysulfone resins, polystyrene resins, polyvinyl alcohol resins, acetic acid. Examples thereof include cellulose resins, polyvinyl chloride resins, and polyacrylate resins. Among these resins, alicyclic structure-containing polymer resins are preferable.
[0017]
  Retardation film made of polymer resin containing alicyclic structure has characteristics such as high transparency, heat resistance, low hygroscopicity, and low photoelasticity.TheIt is well-balanced and has excellent quality stability. Further, the retardation film using the alicyclic structure-containing polymer resin can reduce the wavelength dependency of retardation. If the wavelength dependency of retardation is small, it is not necessary to increase the number of laminated layers, and good broadband properties can be exhibited as a half-wave plate by laminating two sheets.
[0018]
As the wavelength dependence of retardation, the ratio of the retardation value [Re (550)] measured at a wavelength of 550 nm and the retardation value [Re (450)] measured at a wavelength of 450 nm, Re (450) / Re (550). Is preferably 1.02 or less. When the wavelength dependency of retardation is large, that is, when Re (450) / Re (550) is greater than 1.02, three or more multilayers are formed when a wide-band half-wave plate is produced by lamination. It becomes necessary to make it.
[0019]
The alicyclic structure-containing polymer resin is a polymer containing an alicyclic structure in a repeating unit, and examples thereof include a polymer containing an alicyclic structure in a main chain or a side chain. Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of thermal stability.
[0020]
There is no restriction | limiting in particular in carbon number in the hydrocarbon which comprises an alicyclic structure, Usually, 4-30 pieces, Preferably it is 5-20 pieces, More preferably, it is 6-15 pieces. When the carbon number is in such a range, a retardation film excellent in heat resistance and flexibility can be obtained.
[0021]
The proportion of the repeating unit in the polymer containing an alicyclic structure in the repeating unit is appropriately determined according to the intended use of the retardation film, but is usually 50% by mass or more, preferably It is 70 mass% or more, More preferably, it is 90 mass% or more. When the ratio of this repeating unit is too small, the heat resistance of the retardation film may be lowered, which is not desirable. In addition, the ratio of repeating units other than the repeating unit containing an alicyclic structure is also determined appropriately according to the usage mode of the retardation film.
[0022]
Examples of alicyclic structure-containing polymer resins include norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and hydrides of these polymers. Can do. Among these, norbornene-based polymers are preferable from the viewpoints of transparency and moldability.
[0023]
Specific examples of norbornene polymers include ring-opening polymers of norbornene monomers, ring-opening polymers of norbornene monomers and other monomers capable of ring-opening copolymerization, and hydrogenation thereof. Products, addition polymers of norbornene monomers, addition copolymers with other monomers copolymerizable with norbornene monomers, and the like. Among these, from the viewpoint of transparency, a hydrogenated product of a ring-opening polymer of a norbornene-based monomer is most preferable.
[0024]
The said alicyclic structure containing polymer resin is a well-known polymer currently disclosed by Unexamined-Japanese-Patent No. 2002-321302 etc., for example.
[0025]
The glass transition temperature of the alicyclic structure-containing polymer resin preferably used in the present invention is appropriately determined according to the use mode of the retardation film, but is usually 80 ° C. or higher, preferably 100 to 250 ° C. is there. By having such a glass transition temperature, it can be set as the retardation film excellent in durability which does not produce the deformation | transformation and stress in use under high temperature. The molecular weight distribution [weight average molecular weight (Mw) / number average molecular weight (Mn)] of the alicyclic structure-containing polymer resin is not particularly limited, but is usually 1.0 to 10.0, preferably 1.1. It is -4.0, More preferably, it is 1.2-3.5.
[0026]
In the long broadband half-wave plate according to the present invention, the amount of residual volatile components in at least one retardation film among the plurality of laminated retardation films is preferably at most 0.1% by mass. . Examples of the residual volatile component include an unreacted monomer, a low molecular weight polymer, and a solvent used when the resin is produced. This is because the amount of these residual volatile components is at most 0.1% by mass, and even when used for a long period of time, it is stable without causing phase difference unevenness. Incidentally, if the amount of residual volatile components is large, volatile components are released to the outside during use, causing a dimensional change in the wave plate, and internal stress is generated, resulting in in-plane phase difference unevenness.
[0027]
At least one (one layer) retardation film among the plurality of retardation films constituting the long broadband half-wave plate according to the present invention is formed by obliquely stretching the unstretched film made of the thermoplastic resin. .
[0028]
The unstretched film can be obtained by molding the thermoplastic resin into a film. There is no restriction | limiting in particular as a method of shape | molding a thermoplastic resin in a film form, A well-known shaping | molding method, for example, a heat-melt-molding method, a melt casting method, etc. can be mentioned. From the viewpoint of reducing the productivity and the content of residual volatile components in the film to be molded, the heat melt molding method is preferred.
[0029]
Examples of the heat melt molding method include a melt extrusion molding method, a press molding method, an inflation molding method, an injection molding method, and a blow molding method. Among these molding methods, the melt extrusion molding method is preferable.
[0030]
The molding conditions for molding the unstretched film are appropriately determined according to the molding method, but when employing the melt extrusion molding method, the cylinder temperature is preferably 100 to 600 ° C, more preferably 150 to 350 ° C. It is determined appropriately within the range.
[0031]
The thickness of the unstretched film is usually 10 to 300 μm, preferably 30 to 200 μm.
[0032]
In the case of producing an unstretched film, other additives can be added to the thermoplastic resin as long as the object of the present invention is not impaired. Examples of other additives include plasticizers, deterioration inhibitors, and antioxidants.
[0033]
The oblique stretching in the present invention can be performed using an oblique stretching apparatus. As a method of performing an oblique stretching process, particularly if it is a method of continuously stretching in the direction of an angle of 1 to 50 degrees with respect to the width direction of the unstretched film and tilting the orientation axis of the polymer to a desired angle. There is no limitation, and a known method can be adopted.
[0034]
Examples of the oblique stretching method that can be used in the present invention include, for example, JP-A-50-83482, JP-A-2-113920, JP-A-3-182701, JP-A-2000-9912, Examples thereof include methods described in JP-A No. 2002-86554, JP-A No. 2002-22944, and the like.
[0035]
The temperature at which the unstretched film is obliquely stretched is preferably in the range of Tg-30 ° C to Tg + 60 ° C, more preferably in the range of Tg-10 ° C to Tg + 50 ° C, where Tg is the glass transition temperature of the thermoplastic resin. It is. Moreover, a draw ratio is 1.01-30 times normally, Preferably it is 1.01-10 times, More preferably, it is 1.01-5 times.
[0036]
FIG. 3 shows an example of an oblique stretching apparatus. In this oblique stretching apparatus, the feeding speed of the obliquely stretched film fed from the oblique stretching apparatus is made larger than the feeding speed of the unstretched film fed to the oblique stretching apparatus, and in the oblique stretching apparatus, the unstretched film The moving distance of one end in the direction orthogonal to the feed direction of 4, ie, the width direction, is made larger than the moving distance of the other end. However, the linear velocity at both ends of the unstretched film is the same at both ends.
[0037]
In FIG. 3, 4 is an unstretched film, 5 is a film holding start point, 5-1 is a right film holding start point, 5-2 is a left film holding start point, and 6 is a trajectory of the film holding means. 6-1 is the trajectory of the right film holding means, 6-2 is the trajectory of the left film holding means, 7 is the tenter, 8 is the film holding end point, and 8-1 is the right film holding end. 8-2 indicates a film holding end point on the left side, and 9 indicates a diagonally stretched film (long retardation film, hereinafter the same).
[0038]
In this oblique stretching apparatus, the unstretched film fed in is chucked by the left and right film holding start points 5-1 and 5-2 at both ends in the width direction. Although the linear velocity of the film by the left and right film holding means 6-1 and 6-2 is constant, the film moving distance by the left film holding means 6-2 is the film by the right film holding means 6-1. It is set larger than the moving distance. Therefore, the axial direction of the film to be fed, that is, the running direction curves to the right in FIG. At the film holding end point, the film is fed out as an obliquely stretched film 9 whose stretching direction is θ with respect to the width direction of the film.
[0039]
In the present invention, this θ may be obliquely stretched at an angle of 1 to 45 degrees, preferably at an angle of 22.5 ± 2.5 degrees. For example, in the case of two-layer lamination, the crossing angle of the slow axes is set to 45 degrees, so that a combination of a film with an oblique stretching angle of 15 degrees and a film with 30 degrees is also possible. In a preferred embodiment, the two stretched films have the same oblique stretching angle. In this case, it is not necessary to prepare films with different angles, and the oblique stretching angle can be minimized. The angle at this time is 22.5 ± 2.5 degrees.
[0040]
Next, the long and obliquely stretched film 9 produced in this manner is wound up to form a wound roll film 9-1 as shown in FIG. The film 9-2 is uniaxially stretched so that θ = 0 degree or θ = 90 degrees so that the slow axis of the film 9-1 intersects at 45 ± 5 degrees in preparation for the next step. Are obliquely stretched and wound up at an angle of -44 to -1 degrees.
[0041]
When the stretching angle θ of the film 9-1 is 22.5 ± 2.5 degrees, an obliquely stretched film whose stretching direction is an angle θ = −22.5 ± 2.5 degrees with respect to the width direction of the film The film 9-2 is wound up. Alternatively, a stretched film having a stretch angle θ of 22.5 ± 2.5 degrees may be wound in the reverse direction of the film 9-1 to form the film 9-2. The method using the film 9-2 is not particularly limited to these methods as long as the method is excellent in productivity.
[0042]
Subsequently, as shown in FIG. 5, the films 9-1 and 9-2 are respectively sandwiched by the sandwiching rolls 11 and 12, traveled through the feed roll 10, and are sandwiched and stacked by the sandwiching roll 13. The Such a method of laminating is referred to as a “roll-to-roll method”. FIG. 5 shows a lamination mode of two films 9-1 and 9-2. In the present invention, as shown in FIG. 6, three films 9-1, 9-2 and 9 are shown. -3 can also be laminated.
[0043]
At this time, an adhesive or a pressure-sensitive adhesive is applied to the joining surfaces of the two wound roll-shaped films. In this way, an elongated broadband half-wave plate is manufactured. In the manufactured long wideband half-wave plate, a half-wave phase difference is given in a wide wavelength region, for example, a region of 450 to 650 nm. Therefore, the long wideband half-wave plate manufactured as described above has the two long films 9-1 and 9-2 as described above, and their slow axes are 45 ± 5 each other. It is preferable to stack the layers so as to obtain a degree.
[0044]
A long broadband half-wave plate of the present invention is shown in FIG. In FIG. 7, 14 is a long broadband half-wave plate, 15 is a long retardation film having a slow axis in the direction indicated by arrow A by oblique stretching, and 16 is arrow B by oblique stretching. A long retardation film having a slow axis in the direction represented by. In the long broadband half-wave plate of the present invention, the long retardation film 15 and the long retardation film 16 are so arranged that their slow axes intersect each other at a predetermined angle (θ). Are stacked. The angle formed between the width direction of each retardation film and the slow axis can be adjusted as appropriate by controlling the processing conditions for oblique stretching.
[0045]
Furthermore, the long wideband half-wave plate according to the present invention has a wide wavelength region, for example, a region of 450 to 650 nm, and the value of Re / λ is in the range of 0.47 to 0.53. preferable. This is because when the value of Re / λ is within the above range, a more excellent function as a half-wave plate can be achieved in the visible light region with a wavelength of 450 to 650 nm.
[0046]
The thickness of the long broadband half-wave plate of the present invention is preferably 20 to 500 μm, more preferably 50 to 300 μm. The long broadband half-wave plate thus obtained is cut into an appropriate shape or punched into a broadband half-wave plate.
[0047]
This broadband half-wave plate is a wave plate that can give a predetermined phase difference over a wide wavelength range with little change in the value of Re / λ with a change in wavelength, such as a liquid crystal projector, a liquid crystal display, etc. It is a wave plate that can be used effectively in various liquid crystal display devices. Among these, it is suitable as a wave plate for a liquid crystal projector.
[0048]
The liquid crystal projector of the present invention has a broadband ½ wavelength plate obtained from the elongated broadband ½ wavelength plate according to the present invention. An example of the liquid crystal projector of the present invention will be described with reference to FIG.
[0049]
In FIG. 8, 17 is a light source, 18 is a fly-eye lens, 19 is a PS converter, 20 is a reflecting mirror, 21 is a dichroic mirror, 22 is an LCD, 23 is an X-cube prism, and 24 is a projector. Reference numeral 25 denotes a lens, and reference numeral 25 denotes a screen.
[0050]
As shown in the principle diagram of FIG. 9, the PS converter is disposed on each of the polarization beam splitter 27 and the front surface of the p-wave transmission portion from which the p-wave separated by the polarization beam splitter 27 is emitted. And a broadband half-wave plate 28 obtained from the long broadband half-wave plate according to the invention.
[0051]
In the liquid crystal projector employing the PS converter incorporating the broadband half-wave plate according to the present invention, the light emitted from the light source 17 enters the fly-eye lens 18 as a parallel light beam. The emitted light is separated in the polarization beam splitter 27 into p-waves and s-waves whose vibration planes are shifted from each other by 90 °. The p wave is incident on the broadband half-wave plate disposed in front of the traveling direction of the p wave emitted from the polarization beam splitter 27, and the incident p wave is emitted as an s wave.
[0052]
Since a broadband half-wave plate is not disposed in front of the s-wave exit surface from which the s-wave exits the polarizing beam splitter 27, only the s-wave is emitted from the PS converter 27, resulting in a dichroic mirror. 21 is incident. Therefore, according to the liquid crystal projector according to the present invention, the polarized light can be projected onto the dichroic mirror without reducing the amount of light.
[0053]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[0054]
(Production Example 1)
A pellet of a norbornene polymer (ZEONOR 1420, manufactured by Nippon Zeon Co., Ltd., Tg 135 ° C.) is dried at 70 ° C. for 2 hours using a hot air dryer in which air is circulated, and then melted with a 65 mmφ screw. Using a T-die film melt extrusion molding machine having a kneader, a film having a thickness of 100 μm was extruded under the conditions of a molten resin temperature of 240 ° C. and a T-die width of 500 mm.
[0055]
Example 1
The film obtained in Production Example 1 was heated to 135 ° C., introduced into a tenter stretching machine shown in FIG. 3, and subjected to continuous oblique stretching, a stretching ratio of 1.5 times, an average thickness of 70 μm, A long stretched film having an average orientation axis of 22.5 degrees with respect to the width direction was obtained.
[0056]
It was 0.01 mass% when the amount of residual volatile components of the obtained stretched film was measured. The residual volatile component amount was quantified by gas chromatography as the total of components having a molecular weight of 200 or less.
[0057]
The retardation film made of the stretched film thus prepared has a retardation value [Re (550)] at a wavelength of 550 nm of 270 nm, and Re (550) and a retardation value at a wavelength of 450 nm [Re (450)]. The ratio Re (450) / Re (550) was 1.005.
[0058]
Two stretched films are prepared, and one of them is a first retardation film (R1) having a slow axis in a direction substantially +22.5 degrees with respect to the width direction, and the other front and back surfaces are reversed. This was used as a second retardation film (R2) having a slow axis substantially in the direction of -22.5 degrees with respect to the width direction.
[0059]
Next, the first retardation film (R1, 9-1 shown in FIG. 5) and the second retardation film (R2, 9-2 shown in FIG. 5) are stretched by the roll-to-roll method shown in FIG. According to the lamination mode of the film, lamination is carried out via an acrylic pressure-sensitive adhesive layer (Nogawa Chemical Co., Ltd., DD-624, thickness 10 μm) so that the respective longitudinal directions coincide (the slow axis crossing angle becomes 45 degrees). Then, this laminated body was supplied to the nip of the pressure roller and continuously bonded thereto, thereby producing a long broadband 1/2 wavelength plate.
[0060]
The retardation value (Re) of the long broadband half-wave plate produced in this way was measured by KOBRA manufactured by Oji Scientific Instruments. Re / λ at wavelengths of 450, 550, and 650 nm were 0.503, 0.509, and 0.478, respectively. Since the value of Re / λ is 0.5 ± 0.3 in a wide wavelength region including wavelengths of 450 to 650 nm, it was confirmed that it has an excellent function as a broadband half-wave plate. .
[0061]
(Production Example 2)
A pellet of polycarbonate resin (trademark AD5503, manufactured by Teijin Chemicals Ltd., Tg 160 ° C.) is dried at 70 ° C. for 2 hours using a hot air dryer in which air is circulated, and then has a resin melt kneader equipped with a 65 mmφ screw. Using a T-die type film melt extrusion molding machine, a film having a thickness of 100 μm was extruded under the conditions of a molten resin temperature of 270 ° C. and a T-die width of 500 mm.
[0062]
  (referenceExample 2)
  The film obtained in Production Example 2 was heated to 150 ° C., introduced into the tenter stretching machine shown in FIG. 3, and subjected to continuous oblique stretching, a stretching ratio of 1.3 times, an average thickness of 80 μm, A long stretched film having an average orientation axis of 30 degrees with respect to the axial direction was obtained.
[0063]
Separately, the film obtained in Production Example 2 was heated to 150 ° C. and uniaxially stretched in the width direction, the stretching ratio was 1.3 times, the average thickness was 80 μm, and the orientation axis with respect to the width direction of the film was A long stretched film having an average of 0 degrees was obtained. When the amount of residual volatile components was measured for the obtained two types of stretched films having different orientation axes, they were both 0.05% by mass.
[0064]
The retardation value [Re (550)] of the retardation film made of the stretched film thus prepared is 270 nm, and the ratio between Re (550) and the retardation value [Re (450)] at a wavelength of 450 nm. Re (450) / Re (550) was 1.06.
[0065]
Two retardation films stretched obliquely are produced, and one is used as a first retardation film (S1) having a slow axis in a direction substantially +30 degrees with respect to the width direction, and the other front and back surfaces are reversed. This was used as a second retardation film (S2) having a slow axis substantially in the direction of -30 degrees with respect to the width direction. Moreover, the retardation film obtained by uniaxially stretching in the width direction was used as a third retardation film (S3) having a slow axis in a direction substantially 0 degrees with respect to the width direction.
[0066]
Next, the first retardation film (S1, 9-1 shown in FIG. 6), the second retardation film (S2, 9-2 shown in FIG. 6), and the third retardation film (S3, FIG. 6) In accordance with the laminated mode of stretched films by the roll-to-roll method shown in FIG. 6, the respective longitudinal directions coincide with each other (retardation film S1). The angle between the slow axis of the retardation film S3 and the slow axis of the retardation film S3 is 30 degrees, the angle between the slow axis of the retardation film S3 and the slow axis of the retardation film S2 is 30 degrees, and the retardation film S1 Lamination is performed via an acrylic pressure-sensitive adhesive layer (Nogawa Chemical, DD-624, thickness 10 μm) so that the slow axis and the slow axis of the retardation film S2 form an angle of 60 degrees. The body is continuously fed to the nip of the pressure roller A long broadband half-wave plate was manufactured by bonding.
[0067]
The retardation value (Re) of the long broadband half-wave plate produced in this way was measured by KOBRA manufactured by Oji Scientific Instruments. Re / λ at wavelengths of 450, 550, and 650 nm were 0.519, 0.510, and 0.473, respectively. Since the value of Re / λ is 0.5 ± 0.3 in a wide wavelength region including wavelengths of 450 to 650 nm, it was confirmed that it has an excellent function as a broadband half-wave plate. .
[0068]
  According to the present invention, it is possible to efficiently manufacture in one roll-to-roll process using two long-shaped retardation films stretched obliquely without requiring a batch bonding process as in the prior art.YouLong broadband half-wave plateManufacturing methodCan only provideAlso wideExcellent light transmittance over a wide bandIt is possible to provide a method for producing an elongated broadband half-wave plate.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an elongated broadband half-wave plate of the present invention.
FIG. 2 is a cross-sectional view showing another example of an elongated broadband half-wave plate of the present invention.
FIG. 3 is a diagram showing an example of a production mode of a retardation film stretched obliquely.
FIG. 4 is a view showing a stretched film wound up in a roll shape.
FIG. 5 is a diagram showing an example of a laminated mode of stretched films by a roll-to-roll method.
FIG. 6 is a diagram showing an example of another lamination mode of a stretched film by a roll-to-roll method.
FIG. 7 is a diagram showing an example of a manufacturing mode of a long-band broadband half-wave plate according to the present invention and a manufactured broadband half-wave plate.
FIG. 8 is a diagram showing a liquid crystal projector of the present invention.
FIG. 9 is a diagram illustrating the principle of a PS converter.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Broadband half wave plate, 2, 2-1, 2-2 ... Retardation film,
3 ... adhesive layer or pressure-sensitive adhesive layer, 4 ... unstretched film, 5 ... film retention start point,
6 ... film holding means, 7 ... tenter, 8 ... film holding end point,
9 ... Obliquely stretched film, 10 ... Feed roll, 11 ... Nipping roll,
12 ... sandwiching roll, 13 ... sandwiching roll, 14 ... elongate broadband half-wave plate,
15 ... retardation film, 16 ... retardation film, 17 ... light source,
18 ... Compound eye lens, 19 ... PS converter, 20 ... Reflector,
21 ... Dichroic mirror, 22 ... LCD, 23 ... X-cube prism,
24 ... projector lens, 25 ... screen

Claims (6)

Two a stacked method of manufacturing elongate broadband half waveplate comprising as its longitudinal direction retardation film long match, in a width direction orthogonal to the longitudinal direction of the unstretched film On the other hand , an obliquely stretched film that is the retardation film is formed by obliquely stretching in the stretching direction in which the stretching angle θ is 22.5 ± 2.5 degrees, and the winding film obtained by winding the obliquely stretched film and the above an inverse winding film wound in the opposite direction with respect to the winding film, the production of elongated broadband half waveplate each stretching direction, characterized in that laminated by roll-to-roll method so as to intersect Way . The obliquely stretched film is stretched so that both ends in the width direction of the unstretched film are fed at the same linear velocity, and the moving distance at one end in the width direction of the unstretched film is larger than the moving distance at the other end. method of manufacturing elongate wideband half wavelength plate according to claim 1 that will be formed by using the oblique stretching device. 3. The method for producing a long wideband half-wave plate according to claim 1, wherein each of the retardation films has a retardation value Re (550) measured at a wavelength of 550 nm of 275 ± 10 nm. The method for producing an elongated broadband half-wave plate according to any one of claims 1 to 3, wherein the retardation film is a film formed of an alicyclic structure-containing polymer resin. 5. The method for producing an elongated broadband half-wave plate according to claim 1, wherein the obliquely stretched film has a residual volatile component amount of at most 0.1 mass% . 6. The method of manufacturing a long broadband 1/2 wavelength plate according to any one of claims 1 to 5, wherein the long broadband 1/2 wavelength plate is for a liquid crystal projector .

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