Lifting method for sheet optical film and device thereof

Abstract

To provide a lifting method for a sheet optical film, which is unlikely to damage a sheet optical film and can stably separate from a pile of sheet optical films piece by piece.SOLUTION: A method in which an uppermost sheet optical film 1 is lifted from a pile 10 that has multiple sheet optical films 1 that are stacked one on another via a suction part 3, includes a lifting process in which the suction part 3 descends to the lowest position to suction the upper surface of the uppermost optical film 1 by the suction part 3, and then the suction part 3 that has suctioned the optical film 1 is lifted, thereby separating the uppermost sheet optical film 1 from the pile 10. The suction part 3 is moved up and down so that the positioning accuracy of the lowest position of the suction part 3 falls within a range of ±0.10 mm.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for separating single-sheet optical films one by one from an assembly having a plurality of stacked single-sheet optical films.

Background Art

[0002] Conventionally, optical films have been used in image display devices such as liquid crystal display devices and organic EL display devices. Examples of the optical film include a polarizing film containing a polarizer, a retardation film, and a light diffusion film. Further, a polarizing film or the like is also used for applications other than image display devices such as polarizing sunglasses and dimming windows. Such an optical film is formed in a predetermined planar shape according to the screen or the like of the image display device in order to be incorporated into the screen or the like of the image display device. In the present specification, an optical film formed in a predetermined shape is referred to as a "single-sheet optical film". Single-sheet optical films are continuously manufactured in a plurality by, for example, cutting out an optical film mother roll (a long strip-shaped optical film or a large-sized optical film) with a cutting blade. The plurality of manufactured single-sheet optical films are stacked one on top of the other and stored. In the present specification, a stack of a plurality of single-sheet optical films is referred to as an "assembly". As a method of mechanically separating single-sheet optical films one by one from the assembly, it is known to adsorb and lift the upper surface of the uppermost single-sheet optical film.

[0003] For example, Patent Document 1 discloses a film separating device 2 in which suction plates 12 that move up and down by a spring lifting device 5 are arranged on both sides in the width direction of a suction hole-free zone 7 (however, the reference numerals attached to Patent Document 1 are cited). This film separating device 2 operates as follows to extract films one by one from a stack of films. That is, the suction plate 12 is lowered by the spring lifting device 5, the uppermost film is adsorbed by the suction plate 12, the suction plate 12 is lifted by the spring lifting device 5 to lift the film, the film is adsorbed at the perforated zone 7, and the perforated zone 7 is driven to convey the film, thereby extracting one film from the stacked pile.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] The device of Patent Document 1 can be applied to general-purpose films, but there are problems in applying it to single-sheet optical films that require high precision. Specifically, the device of Patent Document 1 repeatedly performs vertical movement of raising the suction plate 12 from the lowest position to the highest position and then lowering it from the highest position to the lowest position by the spring lifting device 5. When the suction plate 12 is lowered by the spring lifting device 5, there is a risk that the tip of the suction plate 12 strongly presses into the upper surface of the film, causing a pressing mark on the upper surface of the film. If such a pressing mark occurs on a single-sheet optical film that requires high precision, the single-sheet optical film will lose its product value. Also, when the suction plate 12 is lowered by the spring lifting device 5, the tip of the suction plate 12 may stop at a position slightly separated from the upper surface of the film, and there is a risk that the suction plate 12 does not adsorb the film. Even when the tip of the suction plate 12 stops at a position separated from the film, if the suction force of the suction plate 12 is increased, the film can be adsorbed. However, if the suction force of the suction plate 12 is increased, there is a risk that an adsorption mark will be left on the upper surface of the film. If a scratch due to the adsorption mark occurs on a single-sheet optical film that requires high precision, the single-sheet optical film will lose its product value.

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a method for lifting a single-sheet optical film and a single-sheet optical film lifting device in which the single-sheet optical film is hardly damaged and the single-sheet optical films can be stably separated one by one from deposits.

Means for Solving the Problems

[0007] The inventors of the present invention intensively studied the above problems of the conventional lifting device and found that the cause lies in the poor positioning accuracy of the lowest descending position of the suction plate 12 (corresponding to the suction part of the present invention). And, by moving the suction part up and down so that the positioning accuracy of the lowest descending position of the suction part is within the range of ±0.10 mm, it was found that the single-sheet optical films can be stably separated one by one from the deposits and damage to the single-sheet optical films can be prevented.

[0008] The method of the present invention is a method of lifting the uppermost single-sheet optical film from a stack having a plurality of stacked single-sheet optical films by a suction part, lowering the suction part to the lowest descending position to adsorb the upper surface of the uppermost single-sheet optical film by the suction part, and separating the uppermost single-sheet optical film from the stack by raising the suction part having adsorbed the single-sheet optical film, and moving the suction part up and down so that the positioning accuracy of the lowest descending position of the suction part is within the range of ±0.10 mm.

[0009] In a preferred method of the present invention, the suction part is moved up and down by a cam mechanism. In a preferred method of the present invention, the vertical movement cycle time of the suction part is 0.10 seconds or more, and the distance from the lowest descending position to the highest ascending position of the suction part is 30 mm or less. In a preferred method of the present invention, the single-sheet optical film is lifted by the suction part so that both side regions in the width direction of the single-sheet optical film hang downward. A preferred method of the present invention is that the pair of suction parts are arranged at intervals in the width direction of the single-sheet optical film, the interval between the pair of suction parts is 1 / 2 or less of the length in the width direction of the single-sheet optical film, and the midpoint between the pair of suction parts and the midpoint in the width direction of the single-sheet optical film substantially coincide. A preferred method of the present invention is that the pair of suction parts are arranged at intervals in the width direction of the single-sheet optical film, and a conveyor belt for sucking and conveying the uppermost single-sheet optical film lifted by the suction parts is arranged between the pair of suction parts. The first suction part does not contact the first side edge in the width direction of the conveyor belt during vertical movement and is arranged within 25 mm from the first side edge. The second suction part does not contact the second side edge in the width direction of the conveyor belt during vertical movement and is arranged within 25 mm from the second side edge.

[0010] According to another aspect of the present invention, a device for lifting a single-sheet optical film is provided. The lifting device of the present invention has a vertically movable suction part for lifting the uppermost single-sheet optical film from an assembly having a plurality of stacked single-sheet optical films, and a lifting part for vertically moving the suction part. The suction part sucks the upper surface of the uppermost single-sheet optical film by descending to the lowest position, separates the uppermost single-sheet optical film from the assembly by ascending the suction part, and the suction part moves vertically so that the positioning accuracy of the lowest position of the suction part is within the range of ±0.10 mm.

[0011] In a preferred device of the present invention, the lifting part vertically moves the suction part by a cam mechanism. In a preferred device of the present invention, the suction part is arranged with respect to the single-sheet optical film such that both side regions in the width direction of the lifted single-sheet optical film hang downward. In a preferred apparatus of the present invention, the pair of suction parts are arranged at intervals in the width direction of the sheet-fed optical film, the interval between the pair of suction parts is 1 / 2 or less of the length in the width direction of the sheet-fed optical film, and the pair of suction parts are arranged with respect to the sheet-fed optical film such that the midpoint between the pair of suction parts substantially coincides with the midpoint in the width direction of the sheet-fed optical film. In a preferred apparatus of the present invention, the elevating part has a piston rod that moves up and down by a cam mechanism and an arm that extends inward from the piston rod, and the suction part is provided on the arm.

Effects of the Invention

[0012] According to the method and apparatus of the present invention, it is possible to separate and take out the sheet-fed optical films one by one from the deposits while preventing damage to the sheet-fed optical films.

Brief Description of the Drawings

[0013]

Figure 1

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Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0014] In this specification, "plan view" means viewing an object from a vertical direction with respect to the surface of the object, and "plan view shape" and "plan view drawing" mean the shape and drawing of the object when viewed from a vertical direction with respect to the surface of the object. Also, in this specification, the expression "substantially" means including the range acceptable in the technical field of the present invention. Further, in this specification, the numerical range represented by "lower limit value X to upper limit value Y" means not less than the lower limit value X and not more than the upper limit value Y. When a plurality of said numerical ranges are separately described, any lower limit value and any upper limit value can be selected.

[0015] [Single-sheet optical film] FIG. 1 is a plan view of a single-sheet optical film. The single-sheet optical film is in a single-sheet form, and its plan view shape is not particularly limited. Examples of the plan view shape of the single-sheet optical film include substantially polygonal shapes such as substantially rectangular, substantially square, substantially trapezoidal, and substantially triangular shapes in plan view; substantially circular shapes; substantially elliptical shapes; and other irregular shapes. The "substantially" in the substantially polygonal shapes such as the substantially rectangular shape includes, for example, a shape with chamfered corners, a shape with a slightly bulging or recessed part of the side, a shape with a slightly curved side, etc. Also, the "substantially" in the substantially circular shape and substantially elliptical shape includes, for example, a shape with a slightly bulging or recessed part of the circumference, a shape with a part of the circumference being slightly straight or slanted, etc. The single-sheet optical film in the illustrated example is in a substantially rectangular shape with the width direction as the major axis and the length direction as the minor axis. Note that the length direction is a direction orthogonal to the width direction.

[0016] The single-sheet optical film includes an optical film. The single-sheet optical film may be composed of only the optical film, or may have the optical film and components other than the optical film. Figures 2 and 3 illustrate the layer structure of the single-sheet optical film. The single-sheet optical film 1 has an optical film 11, a separator film 13, and an adhesive layer 12 interposed between the optical film 11 and the separator film 13 to bond the two films 11 and 13 together. The adhesive layer 12 is firmly adhered to the optical film 11 and is removably adhered to the separator film 13. The separator film 13 can be peeled off at the interface with the adhesive layer 12. Note that a single-sheet optical film without the adhesive layer 12 and the separator film 13 may also be used (not shown).

[0017] The optical film 11 includes an optical functional film. Examples of the optical functional film include a polarizer, a retardation film, a light diffusion film, a brightness enhancement film, an antiglare film, and a light reflection film. The polarizer is a film having the property of transmitting light vibrating in a specific one direction (polarized light) and blocking light vibrating in other directions. The retardation film is a film exhibiting optical anisotropy, and typically includes, for example, a stretched film such as an acrylic resin, a cycloolefin resin, or a cellulose resin. In addition, the optical film 11 may include a protective film. The protective film is laminated for the purpose of protecting the optical functional film. Typically, a colorless and transparent film is used as the protective film.

[0018] In the single-sheet optical film 1 illustrated in FIG. 2, the optical film 11 has, in order from the bottom of the drawing, a first protective film 111, a polarizer 112, and a second protective film 113. By adhering the respective films 111 to 113 to each other, one laminated film (optical film 11) is formed. In the illustrated example, the first protective film 111 and the polarizer 112, and the polarizer 112 and the second protective film 113 are directly adhered to each other. However, if necessary, an adhesive layer (or an adhesive layer) may be interposed between these films and the respective films may be adhered via the adhesive layer (or the adhesive layer) (not shown). Further, a surface protective film 14 is laminated on the surface of the optical film 11 (the surface of the second protective film 113) via an adhesive layer 15. The surface protective film 14 can be peeled off from the surface of the optical film 11, for example, together with the adhesive layer 15. Note that since the surface protective film 14 and the adhesive layer 15 are provided as necessary, a single-sheet optical film that does not have the surface protective film 14 and the adhesive layer 15 may be used.

[0019] In the single-sheet optical film 1 illustrated in FIG. 3, the optical film 11 has a retardation film 115. Further, a surface protective film 16 is laminated on the surface of the optical film 11 (the surface of the retardation film 115) via an adhesive layer 17. The surface protective film 16 can be peeled off from the surface of the optical film 11 (retardation film 115), for example, together with the adhesive layer 17. Note that since the surface protective film 16 and the adhesive layer 17 are provided as necessary, a single-sheet optical film that does not have the surface protective film 16 and the adhesive layer 17 may be used.

[0020] The adhesive layers 12, 15, and 17 provided on the optical film 11 have adhesiveness at normal temperature and the adhesiveness persists even after peeling, allowing for reattachment. The adhesive layers 12, 15, and 17 are composed of known adhesives. Examples of the adhesive include colorless and transparent acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives, cellulose adhesives, and the like. The thickness of the adhesive layers 12, 15, and 17 is not particularly limited. For example, it is 0.1 μm to 50 μm, preferably 1 μm to 30 μm.

[0021] The separator film 13 is not particularly limited. Usually, a film that does not contain an optical functional film is used. The separator film 13 has a release surface with excellent peelability with respect to the adhesive layer 12. Examples of the separator film 13 include resin films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films; paper; porous films such as woven fabrics, non-woven fabrics, and mesh fabrics; foamed resin films; and the like. Since it has excellent surface smoothness, the separator film 13 is preferably a resin film. Examples of the resin film include polyethylene terephthalate film, polybutylene terephthalate film, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyurethane film, ethylene-vinyl acetate copolymer film, and the like. The thickness of the separator film 13 is not particularly limited. For example, it is 5 μm to 200 μm, preferably 10 μm to 100 μm.

[0022] Note that the optical film 11 is not limited to the layer structures shown in FIGS. 2 and 3 and can be variously modified. For example, the optical film may include two or more optical functional films, or may be composed of only one layer of optical functional film. Also, the single-sheet optical film 1 shown in FIGS. 2 and 3 has a separator film 13 and an adhesive layer 12, but it may be a single-sheet optical film that does not have these.

[0023] The single-sheet optical film 1 can be manufactured by a conventionally known method. For example, the single-sheet optical film can be obtained by cutting out an optical film master roll (a long strip-shaped optical film or a large-sized optical film) with a cutting means. In mechanical manufacturing, a plurality of single-sheet optical films are continuously manufactured by continuously performing a process of cutting out the optical film master roll into a predetermined shape, and the single-sheet optical films are sequentially stacked to form an accumulation. The single-sheet optical film is taken out one by one from the accumulation by a lifting device described later.

[0024] [Lifting Device for Single-Sheet Optical Film] FIG. 4 is a side view of the lifting device 2 when the suction part 3 is in the lowest position, and FIG. 5 is a front view of the lifting device 2 in FIG. 4 (a view of the device 2 in FIG. 4 seen from the right side to the left side of the paper). FIG. 6 is a side view of the lifting device 2 when the suction part 3 is in the highest position, and FIG. 7 is a front view of the lifting device 2 in FIG. 6 (a view of the device 2 in FIG. 6 seen from the right side to the left side of the paper). In each front view, the belt conveyor shown in each side view is omitted. In each figure, the white arrow represents the moving direction (upward and downward) of the suction part 3. Referring to FIGS. 4 to 7, the lifting device 2 has a suction part 3 that sucks and lifts the single-sheet optical film 1, a lifting part 4 that moves the suction part 3 up and down, and a conveyor belt 5 that sucks and conveys the single-sheet optical film 1 lifted by the suction part 3. An accumulation 10 is arranged below the lifting device 2. When necessary, a belt conveyor 6 is arranged to convey the single-sheet optical film 1 separated from the accumulation 10 by the lifting device 2 to another location.

[0025] Specifically, the accumulation 10 has a plurality of stacked single-sheet optical films 1. The accumulation 10 is placed on a pedestal 71. The pedestal 71 is provided with a lifting device 72. The position of the upper surface of the uppermost single-sheet optical film 1 of the accumulation 10 placed on the pedestal 71 is monitored by a sensor (not shown). The lifting device 72 raises and lowers the accumulation 10 including the pedestal 71 according to the information of the sensor so that the upper surface of the uppermost single-sheet optical film 1 of the accumulation 10 reaches a certain height from a reference surface (the reference surface is a fixed surface such as the bottom surface of the container 73 or the floor surface). In addition, in order to facilitate the storage and transportation of the accumulation 10, the accumulation 10 including the pedestal 71 is accommodated in a container 73, for example. The accumulation 10 is set below the suction part 3.

[0026] A pair of suction parts 3 are arranged at intervals in the width direction of the single-sheet optical film 1 (accumulation 10). Hereinafter, one of the suction parts 3 may be referred to as the "first suction part 31", and the other suction part 3 may be referred to as the "second suction part 32". The suction part 3 can move up and down in the vertical direction with respect to the upper surface of the uppermost single-sheet optical film 1 of the accumulation 10 by the lifting part 4. The suction part 3 repeats the up and down movement from the lowest position to the highest position and from the highest position to the lowest position under the action of the lifting part 4. As shown in FIGS. 4 and 5, the suction part 3 that has reached the lowest position sucks the upper surface of the uppermost single-sheet optical film 1 from the accumulation 10. When the suction part 3 that has sucked the single-sheet optical film 1 rises, the uppermost single-sheet optical film 1 is lifted and separated from the accumulation 10. As shown in FIGS. 6 and 7, when the suction part 3 that has sucked the single-sheet optical film 1 reaches the highest position, the conveying belt 5 conveys the single-sheet optical film 1 in the length direction after sucking the single-sheet optical film 1.

[0027] In the present invention, the suction part 3 (the first suction part 31 and the second suction part 32) is moved up and down so that the positioning accuracy of the lowest position is within the range of ±0.10 mm. Since the positioning accuracy of the lowest position is within the range of 0 to 0.10 mm, when the suction part 3 descends to the lowest position, the suction part 3 does not excessively push into the upper surface of the single-sheet optical film 1 at the uppermost stage, and the suction part 3 can stably adsorb the upper surface of the single-sheet optical film 1. Further, since the positioning accuracy of the lowest position is within the range of -0.10 mm to 0, when the suction part 3 descends to the lowest position, even if the suction force of the suction part 3 is relatively low, the upper surface of the single-sheet optical film 1 can be stably adsorbed by the suction part 3. The positioning accuracy of the lowest position of the suction part 3 refers to the variation in the lowest position when the tip 3a of the suction part 3 moves to the lowest position. The positioning accuracy of the lowest position is determined, for example, by moving the suction part 3 up and down 100 cycles, measuring the position of the tip 3a of the suction part 3 at the lowest position in all of the 100 cycles, and extracting the maximum value and the minimum value from the 100 position data. By substituting them into the formula: positioning accuracy of the lowest position of the suction part = ±(maximum value when at the lowest position - minimum value when at the lowest position) / 2, the positioning accuracy of the lowest position can be determined.

[0028] The positioning accuracy of the lowest position of the suction part 3 is preferably within the range of ±0.07 mm, and more preferably within the range of ±0.05 mm. Note that the lowest position of the suction part 3 and the position of the upper surface of the single-sheet optical film 1 at the uppermost stage of the above-mentioned deposit 10 are set to the same height position in terms of design. Also, the designed lowest positions of the first suction part 31 and the second suction part 32 are at the same height position.

[0029] Also, the suction part 3 (the first suction part 31 and the second suction part 32) is moved up and down so that the positioning accuracy of the uppermost position is within the range of ±0.10 mm. Since the positioning accuracy of the uppermost position is within the range of ±0.10 mm, when the suction part 3 rises to the uppermost position, the single-sheet optical film 1 can be smoothly adsorbed onto the conveying belt 5. The positioning accuracy of the uppermost position of the suction part 3 is preferably within the range of ±0.07 mm, and more preferably within the range of ±0.05 mm. The positioning accuracy of the uppermost position of the suction part 3 refers to the variation in the uppermost position when the tip 3a of the suction part 3 moves to the uppermost position. For example, the positioning accuracy of the uppermost position is obtained by moving the suction part 3 up and down 100 cycles, measuring the position of the tip 3a of the suction part 3 at the uppermost position in all 100 cycles, and extracting the maximum value and the minimum value from the 100 position data. By substituting them into the formula: positioning accuracy of the uppermost position of the suction part = ±(maximum value when at the uppermost position - minimum value when at the uppermost position) / 2, the positioning accuracy of the uppermost position can be determined. Note that the position of the uppermost position of the suction part 3 and the lower surface of the conveying belt 5 are set to the same height position in design. Also, the designed uppermost positions of the first suction part 31 and the second suction part 32 are at the same height position.

[0030] The method of adsorbing the single-sheet optical film 1 by the suction part 3 is not particularly limited. Since the adsorption and release of the single-sheet optical film 1 can be easily performed, the air suction method is preferable. Specifically, the suction part 3 is provided at the end of a connecting part 36 fixedly connected to the piston rod 35 of the elevating part 4. Inside the connecting part 36, a tube 37 connected to a suction device (not shown) is inserted. The suction part 3 is formed in a hollow cylindrical shape, and the end of the tube 37 is connected to the hollow part of the suction part 3. By operating the suction device, air is sucked from the tip 3a of the suction part 3 through the tube 37. Due to the suction of air, the tip 3a of the suction part 3 adsorbs the single-sheet optical film 1. The suction force (adhesive force due to suction) of the suction part 3 of the air suction method is not particularly limited. However, if it is too low, there is a risk that the single-sheet optical film 1 may fall during lifting. If it is too high, there is a risk that suction marks may be left on the single-sheet optical film 1. From this perspective, the suction force of the suction part 3 is, for example, 10 kPa to 90 kPa.

[0031] The shape of the suction part 3 is not particularly limited. However, in the illustrated example, the suction part 3 is formed in a hollow substantially frustum-conical shape. Therefore, the tip 3a of the suction part 3 is formed in a substantially circular shape in plan view. Note that the tip 3a of the suction part 3 is not limited to a substantially circular shape in plan view, and may be a substantially square shape, a substantially triangular shape, etc. The suction part 3 may be formed of a relatively hard material such as metal or hard synthetic resin. However, from the perspective of preventing damage to the single-sheet optical film 1, it is preferably formed of a relatively soft material. For example, the suction part 3 is formed of a flexible synthetic resin, rubber, elastomer, etc.

[0032] As shown in FIGS. 5 and 7, a conveyor belt 5 is disposed between the pair of suction parts 3. The conveyor belt 5 adsorbs and conveys the uppermost single-sheet optical film 1 lifted by the suction part 3. The conveyor belt 5 is in a belt shape with a predetermined width in the front view shown in FIGS. 5 and 7, and is an endless loop spanned over a plurality of rollers 51 in the side view shown in FIGS. 4 and 6. The conveyor belt 5 rotates according to the rotation of the roller 51 and conveys the single-sheet optical film 1 in the length direction. The rotation axis 52 of each roller 51 is rotatably supported by a bearing (not shown). The bearing is fixed to a frame (not shown) of the device. By rotating at least one of the plurality of rollers 51 by a driving device (not shown), the conveyor belt 5 rotates in the direction of the arrow shown in FIGS. 4 and 6.

[0033] A plurality of hole parts 5a are formed in the plane of the conveyor belt 5. The hole parts 5a penetrate in the thickness direction of the conveyor belt 5. A suction device 53 is arranged on the side opposite to the lower surface of the conveying belt 5. By operating the suction device 53, the air on the lower surface side of the conveying belt 5 is sucked from the hole portion 5a. Due to the suction of the air, the single-sheet optical film 1 is adsorbed on the lower surface of the conveying belt 5. The suction force (adsorption force due to suction) of the conveying belt 5 of the air suction method is not particularly limited, but if it is too low, the single-sheet optical film 1 may fall during conveyance, and if it is too high, there is a possibility that adsorption marks will be left on the single-sheet optical film 1. From such a viewpoint, the suction force of the conveying belt 5 is, for example, 5 kPa to 90 kPa. The conveying belt 5 is formed of a flexible material, for example, formed of a flexible synthetic resin, rubber, elastomer, or the like.

[0034] The length in the width direction of the conveying belt 5 is not particularly limited, but if it is too small, there is a possibility that the adsorbed single-sheet optical film 1 cannot be stably conveyed. From such a viewpoint, the length A in the width direction of the conveying belt 5 is, for example, 20 mm or more, preferably 30 mm or more. There is no particular upper limit for the length A in the width direction of the conveying belt 5, and it can be appropriately set according to the length in the width direction of the single-sheet optical film 1. For example, the length in the width direction of the conveying belt 5 is 80 mm or less, preferably 60 mm or less. Note that the symbol A indicating the length in the width direction of the conveying belt 5 is attached to FIG. 8.

[0035] Regarding the positional relationship between the suction portion 3 and the conveying belt 5, the suction portion 3 is arranged outside the width direction of the conveying belt 5 so as not to contact the conveying belt 5 during vertical movement. FIG. 8 is a plan view showing the positional relationship among the uppermost single-sheet optical film 1, the pair of suction portions 3, and the conveying belt 5. In FIG. 8, the tip 3a of the suction portion 3 is represented by a circle, and the center B of the tip 3a of the suction portion 3 is represented by a cross. Also, in FIG. 8, a part of the conveying belt 5 is omitted. Referring to FIG. 8, the pair of suction portions 3 are arranged such that the intermediate point C between the pair of suction portions 3 substantially coincides with the intermediate point D in the width direction of the sheet-fed optical film 1. Also, the pair of suction portions 3 are arranged such that the intermediate point C of the pair of suction portions 3 substantially coincides with the intermediate point E in the width direction of the conveyor belt 5. Therefore, the intermediate point C between the pair of suction portions 3, the intermediate point E in the width direction of the conveyor belt 5, and the intermediate point D in the width direction of the sheet-fed optical film 1 all substantially coincide. Note that the intermediate points C, D, and E in the width direction refer to the positions at 1 / 2 of the respective width direction lengths. In this case, the pair of suction portions 3 are arranged symmetrically with respect to the intermediate point E of the conveyor belt 5. By arranging the suction portion 3 and the conveyor belt 5 such that the intermediate points C, D, and E substantially coincide in this way, the sheet-fed optical film 1 can be stably lifted.

[0036] Also, the pair of suction portions 3 are arranged away from the conveyor belt 5 to such an extent that they do not contact the conveyor belt 5. However, if they are too far apart, when the pair of suction portions 3 lift the sheet-fed optical film 1, the sheet-fed optical film 1 corresponding between the pair of suction portions 3 may slightly sag. If the central region of the sheet-fed optical film 1 sags during lifting in this way, it becomes difficult for the conveyor belt 5 to adsorb the sheet-fed optical film 1. For such reasons, it is preferable that the first suction portion 31 is arranged within 25 mm from and does not contact the first side edge 5c in the width direction of the conveyor belt 5 during vertical movement, more preferably within 15 mm from the first side edge 5c, and even more preferably within 10 mm from the first side edge 5c. Similarly, it is preferable that the second suction portion 32 is arranged within 25 mm from and does not contact the second side edge 5d in the width direction of the conveyor belt 5 during vertical movement, more preferably within 15 mm from the second side edge 5d, and even more preferably within 10 mm from the second side edge 5d. Note that the distances H between the first suction portion 31 and the second suction portion 32 and the side edges 5c and 5d in the width direction of the conveyor belt 5 are based on the center B of the suction portion 3.

[0037] The size (area) of the tip 3a of the suction part 3 is not particularly limited. However, if it is too small, the suction force on the single-sheet optical film 1 will be small, and if it is too large, the apparatus will become large-sized. From such a viewpoint, the size of the tip 3a of the suction part 3 is 5 mm to 30 mm in diameter, preferably 8 mm to 20 mm in diameter, based on the case where the tip is substantially circular. When the tip 3a of the suction part 3 is not substantially circular in plan view, the size is the equivalent diameter of a circle.

[0038] Also, the interval between the pair of suction parts 3 is not particularly limited. From the viewpoint of lifting the single-sheet optical film 1 in a state of being curved upwardly convex, the interval F (distance between the centers B of the suction parts 3) between the pair of suction parts 3 is preferably 1 / 2 or less of the length G in the width direction of the single-sheet optical film 1. The state of being curved upwardly convex means a state in which both side regions in the width direction of the single-sheet optical film 1 hang downward as described later. From another viewpoint of lifting the single-sheet optical film 1 in a state of being curved upwardly convex, the first suction part 31 is preferably disposed at a position 15 mm or more away from the first side edge 1c in the width direction of the single-sheet optical film 1, more preferably at a position 40 mm or more away from the first side edge 1c in the width direction of the single-sheet optical film 1, and still more preferably at a position 45 mm or more away from the first side edge 1c. Similarly, the second suction part 32 is preferably disposed at a position 15 mm or more away from the second side edge 1d in the width direction of the single-sheet optical film 1, more preferably at a position 40 mm or more away from the second side edge 1d in the width direction of the single-sheet optical film 1, and still more preferably at a position 45 mm or more away from the second side edge 1d. The distance I between the first suction part 31 and the second suction part 32 from the side edges 1c, 1d of the single-sheet optical film 1 is based on the center B of the suction part 3.

[0039] Regarding the position of the suction part 3 in the length direction of the single-sheet optical film 1, the suction part 3 is disposed in the vicinity of the first side edge 1e in the length direction so as not to protrude from the first side edge in the length direction of the single-sheet optical film 1. For example, the first and second suction portions 31 and 32 do not protrude from the first side edge 1e in the length direction of the single-sheet optical film 1 and are arranged at a small distance J from the first side edge 1e in the length direction. By arranging the suction portion 3 at such a position, it is possible to prevent the first side portion in the length direction of the single-sheet optical film 1 lifted by the suction portion 3 from sagging. By preventing the sagging of the first side portion in the length direction, the first side edge 1e in the length direction of the single-sheet optical film 1 can be conveyed by the conveying belt 5 without contacting the upper portion of the container 73. The specific dimension of the distance J may be appropriately set as long as the first side portion in the length direction of the single-sheet optical film 1 does not sag when lifted. However, the distance J is the length between the centers B of the first suction portion 31 and the second suction portion 32 and the side edge 5e in the length direction of the single-sheet optical film 1.

[0040] The pair of suction portions 3 are moved up and down by the elevating portion 4. FIG. 9 is a reference front view showing the suction portion 3 at the lowest descending position and the highest ascending position in one figure. The suction portion 3 and the single-sheet optical film 1 at the highest ascending position are represented by a dashed-dotted line. The suction portion 3 repeats an up-and-down movement cycle by the elevating portion 4. The up-and-down movement cycle refers to the process of reaching the highest ascending position from the lowest descending position and then reaching the lowest descending position again. The up-and-down movement cycle time of the suction portion 3 is not particularly limited. However, if it is too short, the single-sheet optical film 1 may not be stably adsorbed or the single-sheet optical film 1 may fall during lifting. From this perspective, the up-and-down movement cycle time of the suction portion 3 is preferably 0.10 seconds or more, more preferably 0.15 seconds or more, and even more preferably 0.18 seconds or more. The upper limit of the up-and-down movement cycle time of the suction portion 3 is not particularly limited. However, if it is too long, the processing speed will decrease. Therefore, the up-and-down movement cycle time of the suction portion 3 is preferably 1 second or less, more preferably 0.5 seconds or less. Further, the distance from the lowest position to the highest position of the suction part 3 (vertical movement distance) is not particularly limited. However, if it is too long, there is a risk that the single-sheet optical film 1 may fall during the lifting process. From this perspective, the distance K from the lowest position to the highest position of the suction part 3 is preferably 30 mm or less, more preferably 25 mm or less, and even more preferably 20 mm or less. There is no particular lower limit for the distance K from the lowest position to the highest position, but for example, it is 5 mm or more.

[0041] The elevating part 4 has a piston rod 35 that moves vertically. The elevating part 4 is fixed to a frame (not shown) of the device or the like via a support member 41 so as not to sway vertically, horizontally, or in any other direction. The suction part 3 is fixedly connected to the piston rod 35. Therefore, the suction part 3 can move up and down by the drive of the elevating part 4. The suction part 3 may be provided directly below the piston rod 35, or may be provided offset from the axis of the piston rod 35. From the perspective of facilitating the lifting of the single-sheet optical film in a convex upwardly curved state, the suction part 3 is preferably provided offset inward from the axis of the piston rod 35 with respect to the axis of the piston rod 35. For example, the elevating part 4 has a piston rod 35 that moves vertically and an arm 38 that extends inward from the piston rod 35. The suction part 3 is provided on the arm 38. One end of the arm 38 is fixedly provided at the lower end of the piston rod 35, and the opposite end of the arm 38 extends toward the conveying belt 5 side. The suction part 3 is fixedly provided at the opposite end of the arm 38 via a connecting part 36. By providing the suction part 3 on the arm 38 extending from the piston rod 35, while ensuring a good space between the elevating part 4 including the piston rod 35 and the conveying belt 5, as described above, it becomes easier to arrange the suction part 3 (the first and second suction parts 31, 32) within 25 mm from the first side edge 5c and the second side edge 5d in the width direction of the conveying belt 5, respectively.

[0042] The driving method of the lifting part 4 is not particularly limited as long as the suction part 3 can be moved up and down with the above-mentioned positioning accuracy. Since the positioning accuracy of the suction part 3 is improved, it is preferable that the lifting part 4 moves the suction part 3 up and down by a cam mechanism. Further, by designing the shape and rotation speed of the cam, etc. of the cam mechanism, the up-and-down movement cycle time, up-and-down movement distance, etc. of the suction part 3 can be easily set, and furthermore, the stop time at the lowest descent position and the highest ascent position of the suction part 3 can also be easily set. The cam mechanism refers to a mechanism that changes rotational motion into linear reciprocating motion. Examples of the cam mechanism include those using various cams of mechanical elements such as plate cams, face cams (groove cams), cylindrical cams, spherical cams, inclined cams, end face cams, etc., and those using cams of electronic elements such as electronic cams. In addition, the crankshaft mechanism used in an automobile engine can also change rotational motion into linear reciprocating motion by mechanical elements, and such a crankshaft mechanism is also included in the cam mechanism referred to in the present invention.

[0043] FIG. 10 shows an example of the first lifting part 4 using a cylindrical cam 811. The first lifting part 4 includes a cylindrical cam 811 having a groove 812 formed on its circumferential surface, a driven joint 814 having a pin part 813 fitted into the groove 812, and a case 815 that houses these. The rotation axis 816 of the cylindrical cam 811 is in the vertical direction. Therefore, the cylindrical cam 811 rotates around the vertical direction. Further, the lower end of the driven joint 814 is fixed to the piston rod 35. When the cylindrical cam 811 rotates, the driven joint 814 repeatedly moves up and down according to the shape of the groove 812, and the piston rod 35 (suction part 3) fixed to the driven joint 814 also repeatedly moves up and down following the driven joint 814. FIG. (a) of the same figure shows the state when the suction part 3 reaches the lowest descent position, and FIG. (b) of the same figure shows the state when the suction part 3 is at the intermediate position.

[0044] FIG. 11 shows an example of the second lifting part 4 using a flat plate cam 821. The second elevating part 4 has, for example, a flat cam 821 formed in an oval shape, a driven joint 823 having an upper end part 822 in contact with the peripheral end surface of the flat cam 821, a biasing means 824 (for example, a spring) for biasing the piston rod 35 in the direction of the flat cam, and a case 825 for housing these components. The rotation axis 826 of the flat cam 821 is in a direction orthogonal to the vertical direction. Therefore, the flat cam 821 rotates around the direction orthogonal to the vertical direction. Further, the lower end part of the driven joint 823 is fixed to the piston rod 35. When the flat cam 821 rotates, the driven joint 823 repeatedly moves up and down according to its peripheral shape, and the piston rod 35 (adsorbing part 3) fixed to the driven joint 823 and biased by the biasing means 824 also repeatedly moves up and down. Fig. (a) of the same drawing shows the state when the adsorbing part 3 reaches the lowest position, and Fig. (b) of the same drawing shows the state when the adsorbing part 3 is in the intermediate position.

[0045] Fig. 12 shows an example of the third elevating part 4 using a crankshaft 831. The third elevating part 4 has, for example, a crankshaft 831, a connecting rod 832 connected to the crankshaft 831, and a case 833 for housing these components. The rotation axis 834 of the crankshaft 831 is in a direction orthogonal to the vertical direction. Therefore, the crankshaft 831 rotates around the direction orthogonal to the vertical direction. Further, the upper end part 835 of the connecting rod 832 is rotatably connected to the crankshaft 831, and the lower end part 836 of the connecting rod 832 is rotatably connected to the piston rod 35. When the crankshaft 831 rotates, the connecting rod 832 repeatedly moves up and down while rotating, and the piston rod 35 (adsorbing part 3) connected to the connecting rod 832 also repeatedly moves up and down accordingly. Fig. (a) of the same drawing shows the state when the adsorbing part 3 reaches the lowest position, and Fig. (b) of the same drawing shows the state when the adsorbing part 3 is in the intermediate position.

[0046] [Method for lifting a single-sheet optical film] Using the lifting device 2 having the suction part 3, lift the topmost single-sheet optical film 1 in the stack 10 and separate it from the stack 10. Preferably, lift the single-sheet optical film 1 by the suction part 3 so that both side regions in the width direction of the single-sheet optical film 1 hang downward. Specifically, as shown in FIGS. 4 and 5, lower the suction part 3 to the lowest position by the elevating part 4, and suck the topmost single-sheet optical film 1 by the tip 3a of the suction part 3 of the air suction type. When the elevating part 4 raises the suction part 3, the suction part 3 can lift the topmost single sheet of the single-sheet optical film 1 from the stack 10. In particular, as shown by the dashed-dotted line in FIG. 9, lift the single-sheet optical film 1 by the suction part 3 so that both side regions in the width direction of the single-sheet optical film 1 hang downward. When the single-sheet optical film 1 is lifted in a convexly curved shape in this way, only the topmost single-sheet optical film 1 can be separated from the stack 10 without two or more single-sheet optical films 1 following. By setting the interval between the pair of suction parts 3 and the position of the suction part 3 from the side edge in the width direction of the single-sheet optical film 1 as described above, due to the self-weight of the single-sheet optical film 1, the single-sheet optical film 1 can be lifted in a state where both side regions in the width direction of the single-sheet optical film 1 hang downward.

[0047] As shown in FIGS. 6 and 7, when the suction part 3 is raised to the uppermost position, the single-sheet optical film 1 is adsorbed on the conveyor belt 5. Simultaneously with the adsorption of the conveyor belt 5, the air suction of the suction part 3 is stopped, and the adsorption of the single-sheet optical film 1 by the suction part 3 is released. When the conveying belt 5 adsorbs the single-sheet optical film 1 and rotates the conveying belt 5, as shown in FIG. 13, the single-sheet optical film 1 is conveyed by the conveying belt 5. When the single-sheet optical film 1 is conveyed onto the belt conveyor 6, the adsorption of the conveying belt 5 is released. Subsequently, the single-sheet optical film 1 is conveyed by the belt conveyor 6 to the next process (for example, inspection process, etc.). When the single-sheet optical film 1 is taken out from the stack 10, the lifting device 72 operates to lift the stack 10 by the thickness corresponding to one single-sheet optical film 1. Thereby, the upper surface of the uppermost single-sheet optical film 1 of the stack 10 is held at a constant height. In the above description, the case where the conveying belt 5 rotates when adsorbing the single-sheet optical film 1 has been described. However, the conveying belt 5 may rotate constantly.

[0048] According to the method and apparatus of the present invention, since the suction part 3 moves up and down so that the positioning accuracy of the lowest position is within the range of ±0.10 mm, the suction part 3 can stably adsorb the upper surface of the single-sheet optical film 1 without pushing the upper surface of the uppermost single-sheet optical film 1. Therefore, the single-sheet optical film 1 can be taken out one by one from the stack 10 while preventing damage to the single-sheet optical film 1.

Example

[0049] Hereinafter, examples and comparative examples will be shown to describe the present invention in more detail. However, the present invention is not limited to the following examples.

[0050] [Example 1] An apparatus having a lifting part, a pair of suction parts, and a conveying belt as shown in FIGS. 4 and 5, and a stack in which 500 or more single-sheet optical films are stacked were prepared. <Specifications of the apparatus> For the lifting part, a cam mechanism having a cylindrical cam was used to move the piston rod up and down. An arm extends toward the inside (conveying belt side) at the lower end of the piston rod, and the suction part is fixed to the tip of the arm via a connecting part. The vertical movement cycle time of this lifting part was 0.20 seconds, and the vertical movement distance was 20 mm. Therefore, the vertical movement cycle time of the suction part was 0.20 seconds, and the distance K from the lowest position to the highest position of the suction part was 20 mm (for the symbol K, refer to Fig. 9). For the suction part, a flexible silicone resin circular tip with a diameter of 10 mm was used. The suction method of the suction part was an air suction method using a suction device (model ZK2A07 manufactured by SMC), and the suction force of the suction part was set to approximately 20 kPa. For the conveyor belt, a flexible polyurethane resin belt with a plurality of holes formed at regular intervals was used. The suction method of the conveyor belt was an air suction method using a suction device (model HRB100 manufactured by HWANGHAE ELECTRIC), and the suction force of the conveyor belt was set to approximately 10 kPa. In addition, the width A of the conveyor belt was 40 mm (for the symbol A, refer to Fig. 8).

[0051] <Specifications of Single-Sheet Optical Film> A single-sheet optical film including a polarizing film was used, and the thickness of the single-sheet optical film was 200 μm. Also, the width-direction length G of the single-sheet optical film was 150 mm, and its length-direction length was 70 mm (for the symbol G, refer to Fig. 8).

[0052] <Arrangement of Suction Part and Conveyor Belt for Single-Sheet Optical Film> Referring to Fig. 8, at the midpoint D in the width direction of the single-sheet optical film, the midpoint C between the pair of suction parts 3 and the midpoint E in the width direction of the conveyor belt 5 were made to coincide, and the suction part 3 and the conveyor belt 5 were arranged. Also, the pair of suction parts were arranged such that both the distance I between the first suction part 31 and the first side edge 1c in the width direction of the single-sheet optical film 1 and the distance I between the second suction part 32 and the second side edge 1d in the width direction of the single-sheet optical film 1 were 40 mm. Therefore, both the distance H between the first suction part 31 and the first side edge 5c in the width direction of the conveyor belt 5 and the distance H between the second suction part 32 and the second side edge 5d in the width direction of the conveyor belt 5 were 15 mm. A pair of suction parts were arranged such that the distance J between the first suction part 31 and the first side edge 1e in the length direction of the single-sheet optical film 1 and the distance J between the second suction part 32 and the first side edge 1e in the length direction of the single-sheet optical film 1 were both 10 mm. Also, the deposits were set in the container so that the upper surface of the single-sheet optical film would be at the lowest position in the design of the suction part. The conveyor belt 5 was arranged so that the lower surface of the conveyor belt would be at the highest position in the design of the suction part. Note that the lowest position and the highest position in the design of the suction part can be determined from the structure of the elevating part (cylindrical cam), which is a mechanical driving method.

[0053] The above apparatus was operated, and the uppermost single-sheet optical film was adsorbed and lifted by the suction part, and the lifted single-sheet optical film was adsorbed and conveyed by the conveyor belt 5 for 500 cycles. That is, the operation of taking out the uppermost single-sheet optical film from the deposits was performed 500 times. During the operation of the apparatus, the positioning accuracy of the highest position and the positioning accuracy of the lowest position of the suction part were measured. Specifically, as shown for reference in Fig. 10(a), a distance sensor (laser distance meter, product name "Sensor Head IL-030" manufactured by Keyence Corporation) was fixed at an upper position above the suction part 3, and laser light was irradiated downward (vertically with respect to the upper surface of the arm 38), and the distance to the upper surface of the arm 38 was measured. During the operation of the apparatus, using the distance sensor, the actual position when the suction part was at the highest position and the actual position when the suction part was at the lowest position were measured for 100 cycles. The maximum value and the minimum value were extracted from the 100 position data and substituted into the following formulas 1 and 2 to determine the positioning accuracy of the highest position and the positioning accuracy of the lowest position of the suction part. Formula 1: Positioning accuracy of the highest position of the suction part = ±(maximum value when at the highest position - minimum value when at the highest position) / 2. Formula 2: Positioning accuracy of the lowest position of the suction part = ±(maximum value when at the lowest position - minimum value when at the lowest position) / 2. Note that since the vertical length from the upper surface of the arm 38 to the lower surface of the suction part 3 remains unchanged even when the suction part 3 moves up and down, the variation in the measured value up to the upper surface of the arm 38 is equal to the variation in the measured value of the lower surface of the suction part 3. Therefore, by measuring the distance up to the upper surface of the arm 38, it is possible to evaluate the positioning accuracy of the suction part.

[0054] During the operation of the apparatus, the number of single-sheet optical films lifted by the suction part and dropped midway was measured. As a result, the number of dropped sheets was zero out of 500 sheets. Also, during the operation of the apparatus, when the uppermost single-sheet optical film was lifted by the suction part, the number of times the single-sheet optical film below it was also lifted accordingly was measured. As a result, the number of times 2 single-sheet optical films were lifted by the suction part was zero out of 500 cycles. Both sides of 500 single-sheet optical films separated from the deposits and taken out were visually observed to confirm the presence or absence of defects such as scratches and bubbles. As a result, the number of defective products was zero out of 500 sheets.

[0055] [Table 1]

[0056] [Example 2] In the same manner as in Example 1, except that the rotational speed of the cylindrical cam was increased, the lifting of the single-sheet optical film by the suction part and the conveyance by the conveyance belt were performed for 500 cycles. Note that in Example 2 where the rotational speed of the cylindrical cam was increased, the vertical movement cycle time of the suction part was 0.14 seconds. In the same manner as in Example 1, Example 2 also measured the positioning accuracy of the uppermost and lowermost positions of the suction part, and further measured the number of dropped sheets, the number of times 2 single-sheet optical films were lifted, and the number of defective products. The results are shown in Table 1.

[0057] [Example 3] The pair of suction parts were arranged such that both the distance I between the first suction part 31 and the first side edge 1c in the width direction of the single-sheet optical film 1 and the distance I between the second suction part 32 and the second side edge 1d in the width direction of the single-sheet optical film 1 were 10 mm. Except for this, in the same manner as in Example 1, the single-sheet optical film was lifted by the suction parts and conveyed by the conveyor belt for 500 cycles. In the same manner as in Example 1, in Example 3, the positioning accuracy of the uppermost position and the lowermost position of the suction part was measured. Further, the number of dropped sheets, the number of times two single-sheet optical films were lifted, and the number of defective products were counted. The results are shown in Table 1.

[0058] [Comparative Example 1] Except for using an air cylinder type lifting part instead of the cylindrical cam, in the same manner as in Example 1, the single-sheet optical film was lifted by the suction parts and conveyed by the conveyor belt for 500 cycles. In the same manner as in Example 1, in Comparative Example 1, the positioning accuracy of the uppermost position and the lowermost position of the suction part was measured. Further, the number of dropped sheets, the number of times two single-sheet optical films were lifted, and the number of defective products were counted. The results are shown in Table 1.

Explanation of Signs

[0059] 1 Single-sheet optical film 2 Lifting device 3 Suction part 31 First suction part 32 Second suction part 4 Lifting part 5 Conveyor belt 5a Hole part of the conveyor belt 5c First side edge in the width direction of the conveyor belt 5d Second side edge in the width direction of the conveyor belt F Spacing between the pair of suction parts G Length in the width direction of the single-sheet optical film

Claims

1. A method for lifting the uppermost sheet optical film from an assembly having a plurality of stacked sheet optical films, comprising: lowering the suction portion to the lowest position to adsorb the upper surface of the uppermost sheet optical film by the suction portion, and separating the uppermost sheet optical film from the assembly by raising the suction portion that has adsorbed the sheet optical film, the method having a lifting step; A method for lifting a sheet optical film, wherein the suction portion is moved up and down so that the positioning accuracy of the lowest position of the suction portion is within a range of ±0.10 mm.

2. The method for lifting a sheet optical film according to claim 1, wherein the suction portion is moved up and down by a cam mechanism.

3. The method for lifting a sheet optical film according to claim 1 or 2, wherein the vertical movement cycle time of the suction portion is 0.10 seconds or more, and the distance from the lowest position to the highest position of the suction portion is 30 mm or less.

4. The method for lifting a sheet optical film according to any one of claims 1 to 3, wherein the sheet optical film is lifted by the suction portion so that both side regions in the width direction of the sheet optical film hang downward.

5. The suction portions are arranged in a pair with a gap in the width direction of the sheet optical film, the gap between the pair of suction portions is 1 / 2 or less of the length in the width direction of the sheet optical film, The method for lifting a sheet optical film according to any one of claims 1 to 4, wherein the midpoint between the pair of suction portions substantially coincides with the midpoint in the width direction of the sheet optical film.

6. The suction portions are arranged in a pair with a gap in the width direction of the sheet optical film, a conveyor belt for adsorbing and conveying the uppermost sheet optical film lifted by the suction portion is disposed between the pair of suction portions, the first suction portion is disposed within 25 mm from the first side edge in the width direction of the conveyor belt without contacting the first side edge during vertical movement, The method for lifting a sheet optical film according to any one of claims 1 to 5, wherein the second suction portion is disposed within 25 mm from the second side edge in the width direction of the conveyor belt without contacting the second side edge during vertical movement.

7. A lifting device for a sheet optical film, comprising: a vertically movable suction portion that lifts the uppermost sheet optical film from a stack of a plurality of stacked sheet optical films; and a lifting portion that moves the suction portion up and down. The suction portion descends to the lowest position to adsorb the upper surface of the uppermost sheet optical film, and the suction portion ascends to separate the uppermost sheet optical film from the stack. The lifting device for a sheet optical film, wherein the suction portion moves up and down such that the positioning accuracy of the lowest position of the suction portion is within a range of ±0.10 mm. **Claim 8** The lifting device for a sheet optical film according to claim 7, wherein the lifting portion moves the suction portion up and down by a cam mechanism. **Claim 9** The lifting device for a sheet optical film according to claim 7 or 8, wherein the suction portion is arranged with respect to the sheet optical film such that both side regions in the width direction of the lifted sheet optical film hang downward. **Claim 10** A pair of the suction portions are arranged at intervals in the width direction of the sheet optical film. The lifting device for a sheet optical film according to any one of claims 7 to 9, wherein the distance between the pair of suction portions is 1 / 2 or less of the length in the width direction of the sheet optical film, and the midpoint between the pair of suction portions substantially coincides with the midpoint in the width direction of the sheet optical film. **Claim 11** The lifting portion includes a piston rod that moves up and down by a cam mechanism, and an arm that extends inward from the piston rod. The lifting device for a sheet optical film according to any one of claims 7 to 10, wherein the suction portion is provided on the arm.

Images