JP2008080768A - Apparatus and method for paying out film, apparatus and method for manufacturing optical film, and display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture highly efficiently an optical film having excellent optical properties. <P>SOLUTION: An apparatus for paying out a film pays out the film 5 from a film roll 4 rolled in roll and supplies to objective equipment. The apparatus is provided with a supporting part 14 rotatably supporting the film roll 4, an attitude adjusting device 12, 13 for adjusting an attitude of the supporting part, and tension detecting devices 17a, 17b for detecting tensions in the paying-out direction D1 of the both side ends of the film 5 payed out from the film roll 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a film feeding device and method, an optical film manufacturing device and method, and a display device including the optical film manufactured using these, which are used for manufacturing an optical film such as a retardation film.

  For example, a liquid crystal display (LCD) has features such as high image quality, thinness, light weight, and low power consumption, and is widely used as a flat panel display for television receivers, personal computers, and the like. As a color liquid crystal display, a super-twisted nematic (STN) liquid crystal having a simple matrix structure and a simple structure is known, but the hue of the liquid crystal display is green or yellow-red due to the elliptically polarized light based on the STN liquid crystal. This causes a problem. As one of means for solving this problem, a countermeasure is used in which a phase difference film is used to compensate for a phase difference caused by birefringence of STN liquid crystal and to return elliptically polarized light to linearly polarized light.

  As a method for producing the retardation film, for example, a film obtained by uniaxially stretching an unstretched film in the length direction or the width direction is cut to have a predetermined inclination angle with respect to the side of the stretched film. Thus, a method for obtaining an optical film having an orientation axis in a desired direction is known. However, in this method, since cutting is performed obliquely, there is a problem that even if cutting is performed so as to obtain the maximum area, a cutting loss always occurs and the product yield is not high.

  In order to improve this point, as disclosed in Japanese Patent Laid-Open Nos. 02-113920, 03-182701, and 2000-9912, stretching by a tenter as a film stretching apparatus is performed. A stretching method (hereinafter referred to as oblique stretching) in which the orientation is caused to occur in an oblique direction with respect to the longitudinal direction of the film by performing an oblique direction with respect to the longitudinal direction or by giving a speed difference between the left and right clips of the tenter. Has been proposed). Among these oblique stretching methods, for optical films, the uniformity of molecular orientation and thickness unevenness can be made relatively uniform in the width direction. In many cases, a method of feeding a film is used.

  By the way, a retardation film manufacturing apparatus generally includes a feeding device for feeding a film from a film roll in which an unstretched film is wound into a roll, and a film drawn from the feeding device is stretched at a predetermined high temperature. A stretching device (tenter) that performs the stretching and a winding device that winds up the film stretched by the stretching device. The tenter is provided with a number of clips (gripping parts) that run on a pair of endless rails, and both sides of the film are gripped by these clips to advance, and the film is properly tensioned to give the film. Is a device for stretching

  Here, in normal tenter stretching, since the film traveling direction and the stretching direction are orthogonal to each other, the film feeding direction, the traveling direction, and the winding direction are the same. Therefore, once the film width to be fed is determined, it is relatively easy to adjust the rail width at the entrance of the tenter to stabilize the grip with the clip.

  However, in oblique stretching, an angle element is added, so that the position adjustment work is difficult and requires skill and time, and even if a slight deviation occurs, it causes the clip to come off. It is a cause of lowering. In addition, even if it does not occur until the clip comes off, if the film is supplied to the tenter with the positional relationship shifted, the thickness, retardation (Re), orientation angle, etc. in the obliquely stretched film may become non-uniform. In some cases, a stretched film having good optical properties cannot be produced. Therefore, in the oblique stretching for feeding the film with an angle with respect to the winding direction, the film feeding direction is changed each time in relation to the entrance of the tenter in order to produce films having various orientation angles.・ Adjustment is necessary.

The present invention has been made in view of such problems of the prior art, and improves productivity in manufacturing of optical films and the like, facilitates work, and manufactures optical films having good optical characteristics. The purpose is to be able to.
Japanese Patent Laid-Open No. 02-11939 Japanese Patent Laid-Open No. 03-182701 Japanese Patent Laid-Open No. 2000-9912

  According to the present invention, a film feeding device that feeds a film from a film roll wound in a roll shape and supplies the film to a target device (for example, a film stretching device), and a support device that rotatably supports the film roll; A posture adjusting device (for example, a slide mechanism, a rotary table mechanism) for adjusting the posture of the support device, and a direction along the film feeding direction on one edge side of both side edges of the film fed from the film roll. A film comprising: a first tension detecting device that detects a tension; and a second tension detecting device that detects a tension in a direction along a film feeding direction on the other edge side of both side edges of the film fed from the film roll. A payout device is provided.

  In this invention, since the attitude | position adjustment apparatus and the 1st and 2nd tension | tensile_strength detection apparatus are provided, the tension | tensile_strength difference of the direction along the film delivery direction of a film both-sides edge can be detected. Since it is possible to judge from this tension difference whether the relationship between the film feeding position and direction of the film feeding apparatus and the position and direction of the film inlet of the target apparatus that receives the supply of film from the feeding apparatus is appropriate, Based on this, the posture adjustment device adjusts the posture of the support device, that is, the film feeding position and direction, so that the film feeding position and direction can be optimized in relation to the film inlet of the target device. is there.

  Therefore, the film can be properly fed out and supplied to the target apparatus appropriately and stably without adjusting the position and orientation of the film entrance of the target apparatus and based on the objective data of the tension difference. Therefore, the operation becomes extremely easy, productivity can be improved, and production of an optical film or the like having good performance can be realized with high efficiency according to the specifications of the target apparatus. In addition, the other aspect of this invention and its effect | action and effect become clear in embodiment mentioned later.

  According to the present invention, it is possible to achieve improvement in productivity and ease of work in manufacturing an optical film or the like, and to realize manufacture of an optical film or the like having good optical characteristics.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing a schematic configuration of a stretched film manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a film feeding apparatus employed in this system. This stretched film manufacturing apparatus includes a film feeding device 1 that feeds a film 5 from a film roll 4 in which a long film is wound in a roll shape, and a film 5 that is fed from the film feeding device 1 at a predetermined high temperature. A film stretching device (tenter) 2 for stretching and a film winding device 3 for winding the film 5 stretched by the film stretching device 2 are provided.

[Film roll]
The film roll 4 is a roll of a long film made of a transparent resin that is transparent to a predetermined wavelength. As a raw material of the film, a thermoplastic resin is mainly used, and polycarbonate, polyester, polyethersulfone, polyarylate, polyimide, polyolefin, etc., which are general optical film resins, can be used. Further, polyethylene terephthalate, polyimide, polymethyl methacrylate, polysulfone, polyethylene, polyvinyl chloride, diacetyl cellulose, triacetyl cellulose, alicyclic olefin polymer, or the like may be used. Among these, a resin having a positive intrinsic birefringence value is preferable, and an alicyclic olefin polymer is more preferable. As the film, an unstretched film is mainly used, but it may be a film in which any one of longitudinal stretching, lateral stretching, and oblique stretching has already been performed alone or plural times.

  The alicyclic olefin polymer includes a cyclic olefin random multi-component copolymer described in JP-A No. 05-310845, a hydrogenated polymer described in JP-A No. 05-97978, and JP-A No. 11-124429. And thermoplastic dicyclopentadiene-based ring-opening polymers and hydrogenated products thereof.

  The alicyclic olefin polymer will be described more specifically. An alicyclic olefin polymer is a polymer having an alicyclic structure such as a saturated alicyclic hydrocarbon (cycloalkane) structure or an unsaturated alicyclic hydrocarbon (cycloalkene) structure. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the mechanical strength, The properties of heat resistance and film formability are highly balanced and suitable. The proportion of the repeating unit containing the alicyclic structure in the alicyclic olefin polymer may be appropriately selected, but is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight. That's it. When the ratio of the repeating unit having an alicyclic structure in the alicyclic polyolefin resin is in this range, it is preferable because the transparency and heat resistance of the film are improved.

  Examples of the alicyclic olefin polymer include norbornene resins, monocyclic olefin resins, cyclic conjugated diene resins, vinyl alicyclic hydrocarbon resins, and hydrides thereof. Among these, norbornene-based resins are preferably used because of their good transparency and moldability. Examples of the norbornene-based resin include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, a hydride thereof, and a norbornene structure. An addition polymer of a monomer having a monomer, an addition copolymer of a monomer having a norbornene structure and another monomer, or a hydride thereof. Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, lightness, and the like. Used for.

Examples of the monomer having a norbornene structure include bicyclo [2.2.1] hept-2-ene (common name: norbornene) and tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene. (Common name: dicyclopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4.0. 1 ^2,5 . ^{17, 10} ] dodec-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent in the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. Moreover, these substituents may be the same or different and a plurality may be bonded to the ring. Monomers having a norbornene structure can be used singly or in combination of two or more. Examples of the polar group include a hetero atom or an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfone group.

  Other monomers capable of ring-opening copolymerization with monomers having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene and derivatives thereof; cyclic conjugated dienes such as cyclohexadiene and cycloheptadiene; Derivatives thereof; and the like. A ring-opening polymer of a monomer having a norbornene structure and a ring-opening copolymer of a monomer having a norbornene structure and another monomer copolymerizable with the monomer have a known ring-opening polymerization catalyst. It can be obtained by (co) polymerization in the presence.

  Examples of other monomers that can be addition copolymerized with a monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, and 1-butene, and derivatives thereof; cyclobutene, cyclopentene, And cycloolefins such as cyclohexene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, and the like. These monomers can be used alone or in combination of two or more. Among these, α-olefin is preferable and ethylene is more preferable. An addition polymer of a monomer having a norbornene structure and an addition copolymer of a monomer having a norbornene structure with another monomer copolymerizable with a monomer having a norbornene structure are prepared in the presence of a known addition polymerization catalyst. It can be obtained by polymerization.

  A hydrogenated product of a ring-opening polymer of a monomer having a norbornene structure, a hydrogenated product of a ring-opening copolymer of a monomer having a norbornene structure and another monomer capable of ring-opening copolymerization thereof, Hydrogenated products of addition polymers of monomers having a norbornene structure, and hydrogenated products of addition copolymers of monomers having a norbornene structure and other monomers copolymerizable therewith It can be obtained by adding a known hydrogenation catalyst containing a transition metal such as nickel or palladium to the polymer solution and hydrogenating carbon-carbon unsaturated bonds, preferably 90% or more.

Among norbornene-based resins, as repeating units, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3.0.1 ^2,5 ] decane-7 , 9-diyl-ethylene structure, the content of these repeating units is 90% by weight or more based on the entire repeating units of the norbornene-based resin, and the content ratio of X and the content ratio of Y Is preferably 100: 0 to 40:60 by weight ratio of X: Y. By using such a resin, when a retardation film is produced, there is no dimensional change in the long term, and the optical properties can be excellent in stability.

  The molecular weight of the transparent resin is appropriately selected according to the purpose of use, but is converted to polyisoprene measured by gel permeation chromatography using cyclohexane (toluene if the polymer resin is not dissolved) as a solvent (the solvent is toluene). Sometimes, the weight average molecular weight (Mw) in terms of polystyrene is usually 10,000 to 100,000, preferably 15,000 to 80,000, more preferably 20,000 to 50,000. When the weight average molecular weight is in such a range, the mechanical strength and molding processability of the retardation film are highly balanced and suitable.

  The glass transition temperature of the transparent resin may be appropriately selected according to the purpose of use, but is preferably 80 ° C. or higher, more preferably 100 to 250 ° C. When the glass transition temperature is in such a range, the retardation film can be made excellent in durability without causing deformation or stress during use at high temperatures.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the transparent resin is not particularly limited, but is usually 1.0 to 10.0, preferably 1.1 to 4.0, more preferably 1. It is in the range of 2 to 3.5.

The absolute value of the photoelastic coefficient of the transparent resin is preferably ¹⁰ × 10 -12 ^{Pa -1} or less, more preferably 7 × ¹⁰ -12 ^{Pa -1} or less, 4 × ¹⁰ -12 ^{Pa -1} It is particularly preferred that The photoelastic coefficient C is a value represented by C = Δn / σ where birefringence is Δn and stress is σ. When the photoelastic coefficient of the transparent resin is within such a range, variations in retardation (Re) in the in-plane direction of the retardation film can be reduced.

  The transparent resin contains colorants such as pigments and dyes, optical brighteners, dispersants, heat stabilizers, light stabilizers, UV absorbers, antistatic agents, antioxidants, lubricants, solvents, etc. It may be what was done. The film may be a single layer film or a multilayer film.

[Film stretcher]
Next, the film stretching apparatus 2 will be described with reference to FIG. The film stretching device (tenter) 2 of this embodiment is a traveling direction of the film 5 when being wound up by the film winding device 3 with respect to a traveling direction (feeding direction) D1 of the film 5 fed out by the film feeding device 1. As shown in FIG. 1, the winding direction D2 is a so-called oblique stretching apparatus set so as to cross at an angle θ. This angle θ is appropriately selected from a range of 10 to 60 degrees according to the design of a display device such as a liquid crystal panel in which the manufactured optical film is used.

  The film stretching apparatus 2 includes a temperature-controlled room (not shown) including a preheating zone A, a stretching zone B, and a fixed zone C, and a pair of rails 21 and 21 on the left and right on which a gripping means for transporting the film travels. And at least a gripping clip. The holding clip is fed from the film roll 4 by the film feeding device 1 and grips both ends of the film 5 sequentially supplied to the inlet portion Tin of the film stretching device 2, guides the film 5 into the temperature-controlled room, and the film stretching device 2. The film 5 is opened at the outlet portion Tout (before the film winding device 3). The film 5 released from the grip clip is taken up by the film take-up device 3. Each of the pair of rails 21 has an endless continuous track, and the grip clips that have released the grip of the film 5 at the outlet portion Tout of the film stretching apparatus 2 travel outside and are sequentially returned to the inlet portion Tin. It has become.

  The film 5 is stretched by the tension from the holding clip while passing through the temperature-controlled room composed of the preheating zone A, the stretching zone B, and the fixing zone C. The preheating zone A, the stretching zone B, and the fixed zone C can independently set temperatures, and the temperatures are normally kept constant in each zone. Although the temperature of each zone can be selected as appropriate, the preheating zone A is usually Tg to Tg + 30 ° C. and the stretching zone B is usually Tg to Tg + 20 ° C. with respect to the glass transition temperature Tg (° C.) of the transparent resin constituting the film. Zone C is typically Tg to Tg + 15 ° C. In addition, in order to control the thickness unevenness in the width direction, a temperature difference may be applied in the width direction in the stretching zone B. In order to give a temperature difference in the width direction in the stretching zone B, a method of adjusting the opening degree of the nozzle for sending warm air into the temperature-controlled room so as to make a difference in the width direction, or controlling the heating by arranging the heaters in the width direction, etc. A known method can be used. The length of the preheating zone A, the stretching zone B, and the fixed zone C can be appropriately selected. The length of the preheating zone A is usually 100 to 150% with respect to the length of the stretching zone B, and the length of the fixed zone C is usually normal. 50 to 100%.

  The grip clip travels on the rail 21 whose arrangement can be changed. The rails 21 are arranged so that the film 5 is stretched at a desired stretch ratio. The film running direction is the direction of a line connecting the midpoints of the film width direction from the film feeding device 1 to the film winding device 3. On the boundary between the preheating zone A and the stretching zone B and the boundary day between the stretching zone B and the fixed zone C, a partition plate having a slit through which the film can pass is installed.

  The preheating zone A is a zone in which the film 5 is conveyed while warming without substantially changing the film length (film width) in the direction perpendicular to the film running direction (feeding direction) D1. The stretching zone B is a zone for transporting the film 5 while expanding the film width. The film running direction in the stretching zone B is the direction of a straight line connecting from the midpoint of the film 6 at the boundary between the preheating zone A and the stretching zone B to the midpoint of the film 5 at the boundary between the stretching zone B and the fixed zone C. In the rail arrangement in which the extension zone B is spread on both sides at a constant angle as shown in FIG. 1, it coincides with the traveling direction (feeding direction) of the preheating zone A. However, the film running method in the stretching zone B may not coincide with the running direction of the preheating zone A, that is, it may be crossed.

  The fixed zone C is a zone in which the film 5 is conveyed while being cooled without substantially changing the film width. The film traveling direction of the fixed zone C is a direction parallel to the direction (winding direction) D2 in which the film is wound by the film winding device 3.

  In addition, you may change suitably the temperature at the time of diagonal extending | stretching, and a magnification according to the optical characteristic calculated | required. In general, the stretching temperature is preferably in the range of Tg to Tg + 30 ° C. with respect to the glass transition temperature Tg (° C.) of the transparent resin constituting the film, and the stretching ratio is in the range of 1.3 to 4.5 times. Is preferred.

[Film winder]
The film winding device 3 includes a winding roller that is stretched by the film stretching device 2 so as to have a predetermined orientation axis and sequentially winds the film 5 discharged from the outlet portion Tout of the film stretching device 3. . The winding roller does not adversely affect the characteristics of the film 5 discharged from the outlet portion Tout, and the film 5 is driven with a relatively weak driving force that can be reliably wound around the winding roller. It is driven to wind up. The winding roll is set so that the central axis thereof is substantially orthogonal to the discharge direction (winding direction) D2 of the film 5 by the film stretching device 3.

[Film feeding device]
Next, the structure of the film feeding apparatus 1 is demonstrated with reference to FIG.1 and FIG.2. The film feeding device 1 is a device that is installed in the vicinity of the inlet portion Tin of the film stretching device 2 (see FIG. 1), feeds the film 5 from the film roll 4, and supplies it to the film stretching device 2. As shown in FIG. 2, the film feeding device 1 includes a rotary table mechanism 12 having a rotary table, a slide mechanism 13, a film roll support portion 14, and a plurality of pieces (four in FIG. 2) on the base portion 11. Rolls 15a to 15d. The base portion 11, the rotary table mechanism 12, and the slide mechanism 13 constitute a pedestal portion 16.

  As shown in FIG. 1, the base portion 11 is supported so as to be movable along the rails 18, and the entire film feeding device 1 is relatively located with respect to the inlet portion Tin of the film stretching device 2. It can be positioned and fixed roughly. The movement of the base portion 11 along the rail 18 may be either manual or automatic. Although not shown, a rotation mechanism for positioning and fixing the entire orientation of the film feeding apparatus 1 relatively roughly with respect to the inlet portion Tin of the film stretching apparatus 2 may be provided. . The rotation operation in this case may be either manual or automatic. In FIG. 1, the extending direction of the rail 18 is oblique to the feeding direction D1, but may be orthogonal.

  As shown in FIG. 2, a film roll support portion 14 is provided on the rotary table of the rotary table mechanism 12 via a slide mechanism 13. The rotary table mechanism 12 is a mechanism that rotates the rotary table so that the rotary table can be positioned within a predetermined angle range and at an arbitrary position. The rotation of the turntable is performed by a normal drive mechanism using a rack and pinion mechanism, a servo motor, an encoder for detecting a rotation angle, and the like, and is operated based on a control signal from a control device described later. The angular range in which positioning can be performed can be, for example, about ± 50 degrees left and right (clockwise and counterclockwise) with respect to a predetermined reference, and the positioning resolution can be about 0.1 degrees.

  The slide mechanism 13 is a mechanism that slides the film roll support portion 14 that detachably supports the film roll 4 so that the film roll 4 can be positioned at an arbitrary position within a movement range along a predetermined one axis direction. The slide of the film roll support unit 14 by the slide mechanism 13 is performed by a normal drive mechanism using a rack and pinion mechanism, a servo motor, an encoder for detecting a moving position, and the like, and a control signal from a control device described later is received. Operated on the basis. The slide range that can be positioned can be, for example, about ± 50 mm on the left and right (the + side and the − side in a predetermined one-axis direction) with respect to a predetermined reference, and the positioning resolution can be about 1 mm. The sliding direction of the film roll support portion 14 by the slide mechanism 13 is set to be substantially parallel to the center of the bearing portion that supports the film roll 4 of the film roll support portion 14. In addition, although the one film roll support part 14 is displayed in FIG. 2, you may install two or more.

  The four rolls 15a to 15d are driven rolls that guide the traveling of the film 5, and are rotatably supported by the rotary table 12 via bearings (not shown). Although known materials can be used for the rolls 15a to 15d, it is possible to reduce the weight by applying a ceramic coat to prevent the film from being damaged or by applying chrome plating to a light metal such as aluminum. Is preferred. These rolls 15a to 15d are provided in order to stabilize the trajectory when the film 5 travels. In this example, the number of rolls 15a to 15d is four, but generally three to five are provided.

  Of these four rolls 15a to 15d, one of the rolls 15a to 15c excluding the final roll (the roll closest to the film stretching apparatus 2) 15d (here, for example, the roll 15c) is It is preferable that the rubber roll is nipped by pressure contact. This is because such a nip roll can suppress fluctuations in the drawing tension in the film flow direction. Note that one of the nip rolls may be a driving roller, and the film 5 may be actively fed from the film roll 4 by the driving force. In addition, although these rolls 15a to 15d are pivotally supported on the rotary table here, they are pivotally supported on the slide mechanism 13 so as to be slid integrally with the film roll support portion 14. May be.

  A pair of bearing portions at both ends (left and right) of the final roll 15d are provided with a first tension detection device 17a and a second film tension detection device 17b for detecting the tension generated in the film in the roll 15d. ing. As the film tension detection devices 17a and 17b, for example, load cells can be used. As the load cell, a known tensile or compression type can be used. A load cell is a device that detects a load acting on an applied point by converting it into an electrical signal using a strain gauge attached to the strain generating body.

  By installing the load cell on the left and right bearing portions of the roll 15d, the force exerted on the roll 15d by the traveling film 5, that is, the tension in the film traveling direction generated in the vicinity of both side edges of the film 5 is detected independently on the left and right. Is. Note that a strain gauge may be directly attached to the support constituting the bearing portion of the roll 15d, and the load, that is, the film tension may be detected based on the strain generated in the support. The relationship between the generated strain and the film tension is measured in advance and is known. The detection results by the film tension detection devices 17a and 17b are supplied to a control device described later.

  The film tension detectors 17a and 17b as described above are provided to detect the tension in the vicinity of both side edges of the film 5 in the final roll 15d based on the following findings by the inventors of the present application. is there. When the position and direction of the film 5 fed out from the film feeding apparatus 1 are deviated from the position and direction of the inlet portion Tin of the film stretching apparatus 2, the film in the final roll 15d is in accordance with the amount of deviation. Thus, a difference is generated in the tension in the vicinity of both side edges of FIG. 5, so that the degree of the deviation can be determined by detecting this tension difference. That is, if the position and direction of the film 5 fed out from the film feeding apparatus 1 are appropriate in relation to the position and direction of the inlet portion Tin of the film stretching apparatus 2, the load acting on the roll 15d is roughly even on the left and right. Thus, if the positions of each other are shifted, a difference occurs between the left and right film tensions.

  Accordingly, the film 5 is fed out from the inlet portion Tin of the film stretching device 2 by the above-described two attitude adjustment mechanisms (the rotary table mechanism 12 and the slide mechanism 13) so that the difference between the left and right film tensions in the final roll 15d becomes equal. If the position and angle are adjusted appropriately, gripping by the gripping clip at the entrance portion Tin of the film stretching apparatus 2 can be stabilized, and occurrence of obstacles such as clip detachment can be reduced. The physical properties in the width direction of the film 5 can be stabilized.

[Configuration of control system of film feeding apparatus]
FIG. 3 is a block diagram showing the configuration of the control system of the film feeding apparatus 1. The control system CNT includes a control device C1 including a personal computer or an engineering workstation, an input device (keyboard, mouse, etc.) C2, an external storage device C3, a display device (display display) C4, and the like. Yes. The control system CNT is configured to be able to communicate with a host computer that supervises and manages the entire optical film manufacturing apparatus or the entire manufacturing factory in which a plurality of these manufacturing lines are installed via a LAN or the like. May be.

  The external storage device C3 is a portable information recording medium drive device such as a CD (compact disc), DVD (digital versatile disc) (registered trademark), MO (magneto-optical disc) or FD (flexible disc), or an HD ( hard disk) device. The film feeding control program for the film feeding device 1 executed by the control device C1 and various data necessary for this control are stored in advance in the HD, or those stored in the information recording medium are appropriately set in the drive device. The function is realized by being read. The control system CNT may not be such a system, and for example, a one-chip microcomputer may be used.

  The detection signals from the film tension detection devices 17a and 17b described above are supplied to the control device C1 via an A / D (analog / digital) converter (not shown), and the control device C1 drives the slide mechanism according to the control program. The operations of the slide mechanism 13 and the rotary table mechanism 12 are controlled via the part C5 and the rotary mechanism drive part C6. Here, the control device C1 automatically controls the slide mechanism 13 and the rotary table mechanism 12 based on the detection values of the film tension detection devices 17a and 17b, and the feeding position and direction of the film 5 from the film feeding device 1. Is adjusted as appropriate in relation to the inlet portion Tin of the film stretching device 2, but the detection results by the film tension detection devices 17a and 17b, that is, the left and right tensions of the film 5, respectively, or the tension difference between them. May be displayed on the display device C4, and an operator may manually operate the slide mechanism 13 and the rotary table mechanism 12 to find an appropriate positional relationship by trial and error.

[Processing of control system in film feeding apparatus]
FIG. 4 is a flowchart showing a process (film feeding control program) for optimizing the film feeding position and direction by the film feeding device 1 with respect to the entrance portion Tin of the film stretching device 2, which is executed by the control device C1. It is.

  When the process is started, first, a predetermined threshold value is acquired (S1). As this threshold value, a value input in advance by an operator via the input means C2 or a value stored in the storage device C3 as data is used. This threshold value is given as an absolute value of a difference between detection values by the left and right (one end side and the other end side) film tension detection devices 17a and 17b. It can be said that the smaller the tension difference between the left and right, the more optimal. However, according to the experiments conducted by the present inventors, when the tension difference exceeds 80 N, the physical properties of the film after oblique stretching are disturbed, or the processing is interrupted due to clip detachment. Since it has been found that there are cases where it is unavoidable, it is preferably 80 N or less. Therefore, it is preferable to use 80N as the threshold value, more preferably 60N, and even more preferably 50N.

  Since the tension of the left and right (one and the other of both side edges) of the film 5 in the final roll 15d is such that the trajectory of the film 5 from the feeding of the film 5 from the film feeding device 1 to the grip clip of the film stretching device 2 is stabilized. , Each of which is preferably 300 N or more, and more preferably 400 N or more.

  Next, the detected values by the film tension detectors 17a and 17b are acquired, and the absolute value of the difference is calculated as the tension difference (S2). If the tension difference is calculated, it is determined whether or not this tension difference is less than the threshold value acquired in S1 (S3), and if it is determined that the difference is greater than or equal to the threshold value (in the case of No). Outputs a posture adjustment signal as a control signal for slightly moving or rotating the slide mechanism 13 or the rotary table mechanism 12 to the slide mechanism drive unit C5 or the rotation mechanism drive unit C6 (S4).

  By outputting this attitude adjustment signal, the slide mechanism 13 or the rotary table mechanism 12 is moved or rotated by the amount specified by the attitude adjustment signal. In this case, the movement amount (slide pitch) or the rotation angle (rotation pitch) is determined in advance as an optimum value, and these values are used. Note that the posture adjustment signal may be one for operating the slide mechanism 13 and the rotary table mechanism 12 simultaneously. Which of the slide mechanism 13 and the rotary table mechanism 12 is activated or both are activated is selected according to a predetermined algorithm. For the sliding direction or the rotation direction, that is, the positive direction or the negative direction, the tension difference acquired in S2 is stored sequentially, and the direction in which the tension difference is reduced is selected.

  In S3, when it is determined that the tension difference acquired in S2 is less than the threshold value acquired in S1 (in the case of Yes), the tension difference is determined in advance after it first becomes less than the threshold value. Whether or not the predetermined time has elapsed (S5). If the predetermined elapsed time has not elapsed (in the case of No), the process returns to S2, and if the predetermined elapsed time has elapsed (Yes) In the case), a control signal (fixing instruction signal) for fixing the slide mechanism 13 and the rotary table mechanism 12 is output to the slide mechanism drive unit C5 and the rotation mechanism drive unit C6 (S6), and a series of processes is performed. Exit. The lock mechanism provided in each of the slide mechanism 13 and the rotary table mechanism 12 is actuated by the fixing instruction signal in S6 to fix them. Such a locking mechanism is preferably provided to fix the posture, but may not be provided.

[Production of stretched film]
An operator sets the film roll 4 as a processing object on the film roll support part 14 of the film feeding apparatus 1, draws out the film 5, and guides the rolls 15a to 15d. At this time, since the roll 15c is a nip roll, the film 5 passes through the nip portion. Next, the front end of the film 5 is gripped by the grip clip at the entrance portion Tin of the film stretching device 2, and the position of the film feeding device 1 is rough along the rail 18 with respect to the entrance portion Tin of the film stretching device 2. And the film feeding device 1 is fixed.

  Next, the operation of the optical film manufacturing apparatus is started, that is, the film feeding apparatus 1, the film stretching apparatus 2, and the film winding apparatus 3 are operated. When the leading edge of the film reaches the film winding device 3, the leading edge is connected to the winding roll of the film winding device 3 automatically or manually. In the film feeding device 1, the control device C1 monitors the tension in the vicinity of both side edges of the film by the film tension detecting devices 17a and 17b according to the above-described flowchart (FIG. 4), and the tension difference is less than a predetermined threshold value. Thus, when the slide mechanism 13 and the rotary table mechanism 12 are driven and the state of being less than the threshold value has elapsed for a predetermined time, the film feeding position and direction by the film feeding device 1 are the entrance portion of the film stretching device 2. As a result of optimization with respect to the position and direction of Tin, the control over the slide mechanism 13 and the rotary table mechanism 12 is terminated.

  Thus, in this embodiment, since the film feeding position and direction by the film feeding apparatus 1 are automatically optimized in relation to the position and direction of the inlet portion Tin of the film stretching apparatus 2, it is always stable. The film 5 can be supplied to the film stretching apparatus 2, and an optical film (such as a retardation film) having good physical properties (such as optical characteristics) can be produced. Conventionally, adjustment of the film feeding position and direction has been performed manually by a skilled worker, and this operation has required a lot of man-hours. However, such man-hours and personnel can be reduced. Since the film can be supplied in a stable manner, the occurrence of troubles such as clip disengagement due to the gripping clip is reduced, and the productivity can be greatly improved.

  The film 5 fed by the film feeding device 1 and sequentially supplied to the film stretching device 2 is stretched while passing through the temperature-controlled room of the film stretching device 2 as described above, and discharged from the outlet Tout of the film stretching device 2. Then, a long stretched film is manufactured by being sequentially wound by the film winder 3.

[Manufacture of liquid crystal display devices]
The retardation film cut out from the stretched film described above can be used, for example, for manufacturing a liquid crystal display device. An example of the liquid crystal display device includes a liquid crystal panel that can change the polarization transmission axis by adjusting the voltage and a polarizing plate that is disposed so as to sandwich the liquid crystal panel. The retardation film is used in a liquid product display device for optical compensation, polarization conversion, and the like. In order to send light to the liquid crystal panel, the liquid crystal display device is usually provided with a backlight device in the transmissive liquid crystal display device and a reflector in the reflective liquid crystal display device on the back side of the display surface. Examples of the backlight device include a cold cathode tube, a mercury flat lamp, a light emitting diode, and an EL. As the liquid crystal display device, a reflective liquid crystal display device including a reflective liquid crystal panel is preferable. The liquid crystal panel is not particularly limited by the display mode. Examples thereof include a twisted nematic (TN) mode, a super twisted nematic (STN) mode, and a hybrid alignment nematic (HAN) mode. In addition, in the liquid crystal display device, appropriate components such as a prism array sheet, a lens array sheet, a light diffusing plate, and a brightness enhancement film can be arranged in one or more layers at appropriate positions.

  The stretched film described above can be applied to an organic EL display device, a plasma display device, an FED (field emission) display device, and an SED (surface electric field) display device in addition to the liquid crystal display device.

  Hereinafter, it demonstrates in detail, showing an Example and a comparative example. Evaluation in this example is performed by the following method.

(1) Film tension and left-right tension difference of the feeding part A load cell is attached to the left and right bearing parts of the roll (final roll 15d) closest to the inlet part Tin of the film stretching apparatus 2, and the left and right tensions T1 and T2 are measured. The absolute value of the difference was defined as the tension difference.

(2) Thickness and thickness unevenness Using a snap gauge (Mitutoyo, ID-C112BS), the thickness was measured at intervals of 50 mm in the width direction of the film, and the average value T (μm) was obtained. The thickness unevenness was defined as a difference between the maximum value and the minimum value of the thickness.

(3) Retardation (Re) and its variation Using a phase difference meter (manufactured by Oji Scientific Instruments, KOBRA-21ADH), Re was determined at intervals of 50 mm in the width direction of the film, and the average value was taken as the measured value. The variation in Re was defined as the difference between the maximum value and the minimum value.

(4) Orientation angle θ and its variation Using a polarizing microscope (Olympus, BX51), measured at intervals of 50 mm in the width direction of the film, measured in-plane slow axis, slow axis direction and film width The average value of the angle (orientation angle θ) formed by the direction (direction perpendicular to the winding direction D2) was determined and used as a measured value. The variation in the orientation angle θ was defined as the difference between the maximum value and the minimum value.

Example 1
A pellet of thermoplastic norbornene resin (Zeon Corporation, ZEONOR 1420, glass transition point 137 ° C.), which is a kind of alicyclic olefin polymer, was dried at 100 ° C. for 5 hours. The pellets are supplied to an extruder, melted in the extruder, passed through a polymer pipe and a polymer filter, extruded from a T-die onto a casting drum, cooled, and an unstretched film roll having a thickness of 100 μm and a width of 1200 mm is obtained. It was.

  This unstretched film roll is set in the film feeding apparatus 1 schematically shown in FIG. 3, and the direction (D1) inclined 45 degrees with respect to the winding direction D2 in the tenter type film stretching apparatus (oblique stretching machine) 2 The oblique stretched film is obliquely stretched at a stretching temperature of 140 ° C. and a stretch ratio of 1.5 times, the edge portion is cut off, and an obliquely stretched film whose orientation angle is inclined at 45 ° with respect to the winding direction (longitudinal direction) D2 is 1500 mm in width. Got in. The difference between the left and right film tensions T1 and T2 of the film feeding apparatus 1 (the absolute value of the tension difference) could always be maintained at about 50 N during film formation. The stretching conditions and the properties of the stretched film are shown in Table 1.

Comparative Example 1
When film formation was performed by relying on manual adjustment without performing tension feedback, the difference in tension between the left and right was about 150N. Although the clip did not come off, the film physical properties deteriorated. The stretching conditions and the properties of the stretched film are shown in Table 1.

Comparative Example 2
When film formation was performed by relying on manual adjustment without performing tension feedback, the difference in tension between the left and right was about 300N. Film formation was interrupted by the clip removal within a few minutes after the start, and the position adjustment was repeated. The stretching conditions are shown in Table 1.

  The embodiments and examples described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiments and examples is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

It is a top view which shows schematic structure of the optical film manufacturing apparatus which concerns on embodiment of this invention. It is a perspective view which shows schematic structure of the film delivery apparatus which concerns on embodiment of this invention. It is a block diagram which shows schematic structure of the control system of the film delivery apparatus which concerns on embodiment of this invention. It is a flowchart which shows the process of the control system of the film delivery apparatus which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Film feeding apparatus 2 ... Film drawing apparatus 3 ... Film winding apparatus 4 ... Film roll 5 ... Film 11 ... Base part 12 ... Rotary table mechanism 13 ... Slide mechanism 14 ... Film roll support part 15a-15d ... Roll 17a, 17b ... first film tension detection device, second film tension detection device 21 ... rail Tin ... film stretching device inlet Tout ... film stretching device outlet CNT ... control system C1 ... control device C2 ... input device C3 ... storage device C4 ... display Device C5 ... Slide mechanism drive C6 ... Rotation mechanism drive D1 ... Film feed direction D2 ... Film take-up direction

Claims (14)

A film feeding device that feeds a film from a film roll wound in a roll shape and supplies the film to a target device,
A support device for rotatably supporting the film roll;
A posture adjusting device for adjusting the posture of the support device;
A first tension detecting device for detecting a tension in a direction along a film feeding direction on one edge side of both side edges of the film fed from the film roll;
A film feeding device comprising: a second tension detecting device that detects a tension in a direction along a film feeding direction on the other edge side of both side edges of the film fed from the film roll.   The film feeding device according to claim 1, wherein the posture adjusting device has a slide mechanism that slides the support device along a direction intersecting with a feeding direction of the film.   The film feeding device according to claim 1, wherein the posture adjusting device includes a rotation mechanism that rotates the support device. The first tension detecting device has a load sensor that detects a load acting on one end side of the bearing portions at both ends of the roll that guides the film fed from the film roll,
The said 2nd tension | tensile_strength detection apparatus has a load sensor which detects the load which acts on the other end side of the bearing parts of the both ends of the said roll, The Claim 1 characterized by the above-mentioned. Film feeding device.   5. The apparatus according to claim 1, further comprising a control device that automatically controls the posture adjustment device based on detection values detected by the first tension detection device and the second tension detection device. The film feeding apparatus according to Item.   The control device controls the posture adjustment device such that a difference between a detection value by the first tension detection device and a detection value by the second tension detection device is less than a predetermined value. The film feeding apparatus according to claim 5.   The film feeding device according to claim 6, wherein the predetermined value is 80N. The film feeding device according to any one of claims 1 to 7,
A film stretching device for stretching the film in at least one axial direction in the film plane while advancing the film fed from the film feeding device;
An optical film manufacturing apparatus comprising: a film winding device that winds a film stretched by the film stretching device.   The optical film manufacturing apparatus according to claim 8, wherein the film stretching apparatus is an oblique stretching apparatus that stretches the film in a direction oblique to the longitudinal direction of the film. A film feeding method for feeding a film from a roll film wound in a roll shape,
A first tension detecting step of detecting a tension in a direction along a film feeding direction on one end edge side of both side edges of the film fed from the roll film;
A second tension detecting step of detecting a tension in a direction along a film feeding direction on the other end edge side of both side edges of the film fed from the roll film;
And a posture adjusting step of adjusting the posture of the roll film based on the detection values detected in the first tension detecting step and the second tension detecting step.   The posture adjustment step adjusts the posture of the roll film so that a difference between a detection value obtained by the first tension detection step and a detection value obtained by the second tension detection step is less than a predetermined value. The film feeding method according to claim 10.   The film feeding method according to claim 11, wherein the predetermined value is 80N. An unwinding step of unwinding a film using the film unwinding method according to any one of claims 10 to 12,
A stretching step of stretching the film fed out by the feeding step in at least a uniaxial direction;
And a winding step of winding the film stretched by the stretching step.   A display device comprising the optical film manufactured by the optical film manufacturing method according to claim 13.

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