JP2014104584A - Optical sheet processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical sheet processing apparatus capable of preventing the contamination of an optical sheet by a cutting debris powder adhered thereto.SOLUTION: An optical sheet processing apparatus 20 is furnished with: stages 28A and 28B; a transfer roll 23 having a transfer surface 23a for impressing an uneven pattern 9 onto the incident edge plane 7a of a light guide plate 7 mounted on the stages 28A and 28B; means for heating the transfer roll 23; means for impressing a pressure so as to press the incident edge plane 7a of the light guide plate 7 and the transfer surface 23a of the transfer roll 23 against one another; means for mobilizing the stages 28A and 28B in relation to the transfer roll 23 along the direction for forming the uneven pattern 9; and means for driving the transfer roll 23 upward and downward. In a case where debris are adhered to the transfer surface 23a of the transfer roll 23 following the execution of a molding process, the transfer roll 23 is driven upward or downward so as to shift the contact site of the transfer surface 23a of the transfer roll 23 with the incident edge plane 7a of the light guide plate 7.

Description

  The present invention relates to an optical sheet processing apparatus and method for forming an uneven portion on a light incident end face of an optical sheet.

  An example of the optical sheet is a light guide plate used in a backlight unit of a liquid crystal display device. In the edge-light type backlight unit, a plurality of light sources are arranged in an array facing the light incident end face of the light guide plate, and light incident from the light incident end face of the light guide plate is emitted from the light exit surface, thereby liquid crystal Illuminate the display panel. However, in the edge light type backlight unit, luminance unevenness occurs in the illumination light emitted from the vicinity of the light incident end surface of the light exit surface of the light guide plate.

  In order to solve such a problem, for example, as described in Patent Document 1, a technique in which a cut and polished surface is formed on a light incident end surface of a light guide plate is known. The cutting and polishing surface described in Patent Document 1 is a rough surface having a large number of fine vertical irregularities extending in a direction perpendicular to the light emitting surface of the light guide plate.

JP 2010-182478 A

  However, in the above prior art, the cutting and polishing surface is formed on the light incident end surface of the light guide plate by machining using a machine tool such as a milling machine, NC router, or planar, so that chips are generated by cutting. . For this reason, cutting powder mixes and adheres to the light guide plate, resulting in poor quality.

  The objective of this invention is providing the optical sheet processing apparatus and method which can prevent mixing and adhesion of the swarf to an optical sheet.

  The present invention relates to an optical sheet processing apparatus for forming an uneven portion on a light incident end face of an optical sheet made of a thermoplastic resin, the surface supporting the optical sheet, and the light incident end face of the optical sheet supported by the stage. A metal transfer roll having a transfer surface for applying a portion, a heating means for heating the transfer roll, a pressure applying means for applying pressure so as to press the transfer face and the light incident end face, and rotating the transfer roll A rotating means for moving, a first moving means for moving the stage relative to the transfer roll in the direction of forming the concavo-convex portion, and a second for moving the transfer roll relative to the stage in the roll axis direction of the transfer roll. And a moving means.

  Using such an optical sheet processing apparatus of the present invention, when forming a concavo-convex portion on the light incident end surface of an optical sheet made of a thermoplastic resin, the metal transfer roll is heated and the transfer surface of the transfer roll and With the pressure applied so that the light incident end faces of the optical sheet are pressed against each other, the stage is moved relative to the transfer roll in the direction of forming the concavo-convex part while rotating the transfer roll. An uneven portion is provided on the light end face. Thereby, unlike the case where an uneven | corrugated | grooved part is formed by cutting, since a swarf does not generate | occur | produce, the mixing and adhesion of the swarf to an optical sheet can be prevented.

  Further, for example, when the transfer surface of the transfer roll is thermally transferred to the light incident end surface of the optical sheet, the thermoplastic resin that is the material of the optical sheet is thermally decomposed, and the additive contained in the thermoplastic resin is precipitated. It may adhere to the transfer surface of the transfer roll as dirt. When contamination occurs on the transfer surface of the transfer roll in this way, the transfer roll is placed on the stage so that the incident end surface of the optical sheet does not come into contact with the occurrence of contamination on the transfer surface of the transfer roll. Move relatively in the roll axis direction of the transfer roll. As a result, even if the transfer surface of the transfer roll becomes dirty, the formation of uneven portions on the light incident end surface of the optical sheet is continuously performed on the clean transfer surface of the transfer roll without cleaning the transfer surface. Can do.

  Preferably, a masking film is bonded to the main surface of the optical sheet. In this case, when pressure is applied so as to press the transfer surface of the transfer roll and the light incident end surfaces of the optical sheet, the paste component used for bonding the masking film adheres to the transfer roll as dirt. There is. Therefore, it is particularly effective to apply the present invention to the processing of such an optical sheet with a masking film.

  Preferably, the heating unit includes an induction coil provided in the transfer roll and a power supply unit that supplies current to the induction coil. By using a transfer roll with an induction coil in this way and passing a current through the induction coil to heat the transfer roll, the temperature distribution in the roll axis direction of the transfer roll is higher than when the transfer roll is heated with oil. It is made uniform. Therefore, by moving the transfer roll relative to the stage in the roll axis direction of the transfer roll, stable transfer accuracy can be achieved even if the contact location between the transfer surface of the transfer roll and the light incident end surface of the optical sheet is changed. Can be obtained.

  Moreover, this invention is an optical sheet processing method which forms an uneven | corrugated | grooved part in the light-incidence end surface of the optical sheet which consists of thermoplastic resins, Comprising: While preparing the said optical sheet processing apparatus, heating a transfer roll, In the state where pressure is applied so as to press the transfer surface and the light incident end surface, the light incident end surface is moved relative to the transfer roll in the direction of forming the concavo-convex part while rotating the transfer roll. In order to avoid contact of the light incident end surface with the foreign matter adhesion site on the transfer surface when foreign matter is adhered to the transfer surface after performing the molding step and forming step on the transfer surface And an avoidance step of moving the transfer roll relative to the stage in the roll axis direction of the transfer roll.

  In such an optical sheet processing method of the present invention, the transfer roll is heated and the transfer roll is rotated in a state where pressure is applied so as to press the transfer surface of the transfer roll and the light incident end faces of the optical sheet. By moving the stage relative to the transfer roll in the direction of forming the uneven portion, the uneven portion is imparted to the light incident end surface of the optical sheet. Thereby, unlike the case where an uneven | corrugated | grooved part is formed by cutting, since a swarf does not generate | occur | produce, the mixing and adhesion of the swarf to an optical sheet can be prevented.

  In addition, when foreign matter adheres to the transfer surface of the transfer roll after forming the concavo-convex portion on the light entrance end surface of the optical sheet, it is avoided that the light entrance end surface comes into contact with the foreign matter attachment location on the transfer surface. In this manner, the transfer roll is moved relative to the stage in the roll axis direction of the transfer roll. As a result, even if the transfer surface of the transfer roll becomes dirty, the formation of uneven portions on the light incident end surface of the optical sheet is continuously performed on the clean transfer surface of the transfer roll without cleaning the transfer surface. Can do.

  According to the present invention, it is possible to prevent chips from being mixed and adhered to the optical sheet. Further, even when the transfer surface of the transfer roll is contaminated, it is possible to continuously form the uneven portion on the light incident end surface of the optical sheet on the clean transfer surface of the transfer roll. As described above, the quality of the optical sheet can be stabilized and the yield can be improved.

It is a schematic sectional drawing which shows the liquid crystal display device containing the light-guide plate which is an optical sheet obtained by one Embodiment of the optical sheet processing apparatus concerning this invention. It is a perspective view of the light-guide plate shown in FIG. It is a flowchart which shows the process of manufacturing the light-guide plate shown in FIG. It is a top view which shows one Embodiment of the optical sheet processing apparatus concerning this invention. It is a front view of the optical sheet processing apparatus shown in FIG. It is VI-VI line principal part sectional drawing of FIG. It is a principal part enlarged view of FIG. It is an VIII-VIII line principal part expanded sectional view of FIG. It is a perspective view which shows roughly the optical sheet processing apparatus shown in FIG. FIG. 7 is a cross-sectional view showing a state where a transfer roll is raised in the optical sheet processing apparatus shown in FIG. 6. It is a conceptual diagram which shows an example of the process of shape | molding a light-guide plate using the optical sheet processing apparatus shown in FIG. It is a perspective view which shows the modification of the optical sheet processing apparatus shown in FIG.

  Hereinafter, an optical sheet processing apparatus and method according to the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic sectional view showing a liquid crystal display device including a light guide plate which is an optical sheet obtained by one embodiment of an optical sheet processing apparatus according to the present invention. In the figure, a liquid crystal display device 1 according to this embodiment is used for a liquid crystal television, for example. The liquid crystal display device 1 includes a liquid crystal panel 2 and an edge-type backlight unit 3 disposed on the back side of the liquid crystal panel 2. The thickness of the liquid crystal panel 2 is, for example, about 1.8 mm.

  The backlight unit 3 has a box-shaped metal backlight housing 4. A plurality of electronic components 5 are provided on the back surface (back surface) of the backlight housing 4 via a substrate (not shown). A plurality of LEDs 6 that irradiate light are attached to the opposing inner wall surfaces of the backlight housing 4.

  In the backlight housing 4, a light guide plate 7 having a rectangular cross section for guiding the light emitted from the LEDs 6 to the liquid crystal panel 2 is accommodated via a reflection sheet 8. As shown in FIG. 2, the light incident end surface 7 a of the light guide plate 7 is provided with a concavo-convex portion 9 having a substantially corrugated cross section. The thickness of the light guide plate 7 is, for example, 3 mm.

  The light guide plate 7 is made of a thermoplastic resin. Specifically, the light guide plate 7 is made of an amorphous resin having high dimensional accuracy, impact strength, and transparency. Examples of the amorphous resin include polymethyl methacrylate resin (PMMA), polystyrene (PS), polycarbonate (PC), and cycloolefin polymer (COP). Although not particularly illustrated, it is preferable that a masking film for protection is bonded to the main surface of one side or both sides of the light guide plate 7.

  The masking film is affixed to prevent damage to the main surface of the light guide plate 7. The masking film has a base material and an adhesive layer that is a paste component formed on the base material. The adhesive layer is disposed between the base material and the light guide plate 7. The base material is made of, for example, a polyolefin (PO) resin such as a polypropylene (PP) resin or a polyethylene (PE) resin, a polyethylene terephthalate (PET) resin, or the like. The adhesive layer is formed of, for example, a polyolefin (PO) elastomer, an ethylene / vinyl acetate copolymer (EVA), or the like. The thickness of the masking film is, for example, 40 μm to 90 μm.

  The light emitted from the LED 6 is incident on the light incident end surface 7 a of the light guide plate 7. The back surface of the light guide plate 7 is a reflective surface that reflects the light emitted from the LED 6, and the front surface of the light guide plate 7 is a light exit surface that emits the light emitted from the LED 6 and the light reflected by the reflective surface. It has become. The back surface (reflection surface) of the light guide plate 7 has a structure that easily reflects and scatters light, such as dot pattern printing with ink.

  On the front side of the light guide plate 7, an optical film group 10 formed by laminating a plurality of (here, three) optical films is disposed. The thickness of the optical film group 10 is, for example, about 0.2 mm. The edges of the light guide plate 7 and the optical film group 10 are fixed to the backlight housing 4 by a frame body 11 made of resin (for example, PC). The liquid crystal panel 2 is fixed to the backlight unit 3 by a metal frame body 12.

  FIG. 3 is a flowchart showing a process for manufacturing the light guide plate 7. In the figure, first, a light guide plate original plate is produced by a melt extrusion sheet forming process or the like (step S101). Subsequently, the light guide plate original plate is roughly cut with a panel saw, a running saw, or the like to obtain the light guide plate 7 (step S102). Subsequently, mirror processing is performed on the light incident end surface 7a of the light guide plate 7 using a mirror processing machine (step S103). Then, the uneven | corrugated | grooved part 9 is formed in the light-incidence end surface 7a by performing thermal transfer processing to the light-incidence end surface 7a of the light-guide plate 7 (step S104). Note that step S103 is not necessarily performed.

  FIG. 4 is a plan view showing an embodiment of an optical sheet processing apparatus according to the present invention. 5 is a front view of the optical sheet processing apparatus shown in FIG. 4, FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5, and FIG. 7 is an enlarged view of the relevant part in FIG. 8 is an enlarged cross-sectional view taken along the line VIII-VIII in FIG. FIG. 9 is a perspective view schematically showing the optical sheet processing apparatus shown in FIG. In each figure, the optical sheet processing apparatus 20 of this embodiment is used when step S104 shown in FIG. 3 is performed.

  The optical sheet processing apparatus 20 includes an apparatus frame 21. A rack 22 is disposed at the center of the apparatus frame 21, and a metal transfer roll 23 is rotatably supported on the rack 22 (see FIG. 6). As shown in FIG. 9, a transfer uneven portion 19 is formed on the outer peripheral surface 23 a of the transfer roll 23 along the circumferential direction of the transfer roll 23. The outer peripheral surface 23 a of the transfer roll 23 is a transfer surface for imparting an uneven portion to the light incident end surface 7 a of the light guide plate 7. The transfer uneven portion 19 is formed in a prism shape or a lenticular shape with respect to the roll axis direction of the transfer roll 23, for example.

  As shown in FIG. 6, the transfer roll 23 is an electric heater roll in which an induction coil 41 is built. On the upper side of the transfer roll 23, a power supply unit 42 for supplying a high-frequency current to the induction coil 41 is disposed. The induction coil 41 and the power supply unit 42 constitute a heating unit that heats the transfer roll 23. When a high-frequency current flows through the induction coil 41, an eddy current is generated in the transfer roll 23 by the magnetic field generated in the induction coil 41, and the transfer roll 23 generates heat.

  As shown in FIG. 5, pedestals 25 </ b> A and 25 </ b> B are arranged below the apparatus frame 21 so as to sandwich the transfer roll 23 in the apparatus left-right direction (X direction). Stage bases 26A and 26B are attached to the upper portions of the pedestals 25A and 25B so as to be movable in the longitudinal direction of the apparatus (Y direction) via guide rails 27A and 27B, respectively. Stages 28A and 28B are mounted on the upper portions of the stage bases 26A and 26B so as to be movable in the left-right direction (X direction) of the apparatus via guide rails 29A and 29B, respectively.

  The light guide plate 7 is placed (supported) on the upper surfaces of the stages 28A and 28B. On the upper surfaces of the stages 28A and 28B, light guide plates 7 of various sizes can be placed vertically or horizontally (see FIG. 4). The vertical placement is a placement method in which the longitudinal direction of the light guide plate 7 is matched with the Y direction. The horizontal placement is such that the longitudinal direction of the light guide plate 7 coincides with the X direction. The light guide plate 7 placed on the upper surfaces of the stages 28A and 28B is positioned by positioning means not described in detail. The light guide plate 7 placed on the upper surfaces of the stages 28A and 28B is pressed against the stages 28A and 28B by the clamp plates 18A and 18B (see FIG. 9).

  Press cylinders 30A and 30B for moving the stages 28A and 28B in the X direction are attached to the upper portions of the stage bases 26A and 26B, respectively (see FIG. 5). The pressure cylinders 30A and 30B are pressure applying means for applying pressure to the stages 28A and 28B so as to press the light incident end surface 7a of the light guide plate 7 placed on the stages 28A and 28B against the transfer surface 23a of the transfer roll 23. Is configured.

  5 to 8, the optical sheet processing apparatus 20 is disposed so as to sandwich the transfer roll 23 in an oblique direction with respect to the X direction and the Y direction corresponding to the stages 28A and 28B. Serving motors 31A and 31B are provided. Pinion gears 32A and 32B are attached to the output shafts 31a of the forming servomotors 31A and 31B, respectively. Rack gears 33A and 33B extending in the Y direction and meshing with the pinion gears 32A and 32B are provided on the inner side surfaces of the lower portions of the stage bases 26A and 26B, respectively. As a result, when the molding servomotors 31A and 31B are driven to rotate, the rotation of the molding servomotors 31A and 31B is transmitted to the stage bases 26A and 26B via the pinion gears 32A and 32B and the rack gears 33A and 33B. , 26B move in the Y direction, and accordingly the stages 28A, 28B move in the Y direction.

  Under the rack 22, shafts 34A and 34B extending in the Z direction are rotatably supported. These shafts 34A and 34B are arranged so as to sandwich the transfer roll 23 in the Y direction. Spur gears 35A and 35B that mesh with the above-described pinion gears 32A and 32B are provided in the middle portions of the shafts 34A and 34B, respectively. The shafts 34A and 34B and the spur gears 35A and 35B have a rotary ball spline structure. Electromagnetic clutches 36A and 36B are attached to the upper ends of the shafts 34A and 34B, respectively.

  A support plate 22 a is connected to the rack 22. Shafts 37A and 37B extending downward are rotatably supported at portions corresponding to the shafts 34A and 34B in the support plate 22a. Spur gears 38A and 38B are provided in the middle portions of the shafts 37A and 37B, respectively. The lower ends of the shafts 37A and 37B are attached to the electromagnetic clutches 36A and 36B, respectively.

  The electromagnetic clutch 36A interrupts the transmission of power from the spur gear 35A to the spur gear 38A by intermittently connecting the shafts 34A and 37A. Specifically, when the electromagnetic clutch 36A is ON, the shafts 34A and 37A are connected to each other, and when the electromagnetic clutch 36A is OFF, the connections between the shafts 34A and 37A are released. The electromagnetic clutch 36B interrupts the transmission of power from the spur gear 35B to the spur gear 38B by intermittently connecting the shafts 34B and 37B. Specifically, when the electromagnetic clutch 36B is ON, the shafts 34B and 37B are connected to each other, and when the electromagnetic clutch 36B is OFF, the connections between the shafts 34B and 37B are released.

  A roll shaft 23 b of the transfer roll 23 extends below the rack 22. A spur gear 39 that meshes with the spur gears 38A and 38B is attached to the lower end of the roll shaft 23b.

  A ball screw 43 extending in the vertical direction of the apparatus (Z direction) is disposed on the rear side of the optical sheet processing apparatus 20. The ball screw 43 includes a screw shaft 43a and a nut 43b that meshes with the screw shaft 43a. A main elevating body 44 is attached to the nut 43b. The main lifting body 44 is fixed to one side surface of the rack 22. The screw shaft 43 a is rotated by the lifting servo motor 45. Linear guides 46 extending in the Z direction are disposed on both sides of the rack 22 in the front and rear sides. A plurality of auxiliary lifting bodies 47 slidable along the linear guide 46 are fixed to the side surfaces on both sides of the rack 22. When the screw shaft 43a of the ball screw 43 is rotated by the lifting / lowering servo motor 45, the main lifting / lowering body 44 and the auxiliary lifting / lowering bodies 47 move in the Z direction, and accordingly the rack 22 is lifted and supported by the rack 22. The transfer roll 23 moves up and down.

  In the above, the forming servo motors 31A and 31B, the pinion gears 32A and 32B, the shafts 34A and 34B, the spur gears 35A and 35B, the electromagnetic clutches 36A and 36B, the shafts 37A and 37B, the spur gears 38A and 38B, and the spur gear 39 are Rotating means for rotating the transfer roll 23 is configured. Servo motors 31A and 31B, pinion gears 32A and 32B, rack gears 33A and 33B, stage bases 26A and 26B, and guide rails 27A and 27B are arranged in the direction in which the concavo-convex portion 9 is formed with respect to the stages 28A and 28B. The 1st moving means to move relatively is comprised.

  Further, the rack 22, the ball screw 43, the main elevating body 44, the elevating servo motor 45, the linear guide 46, and the auxiliary elevating bodies 47 make the transfer roll 23 relative to the stages 28A and 28B in the roll axis direction of the transfer roll 23. The second moving means for moving the image automatically is configured.

  When the forming servomotor 31A is driven to rotate with the electromagnetic clutch 36A turned on, transfer is performed via the pinion gear 32A, spur gear 35A, shaft 34A, electromagnetic clutch 36A, shaft 37A, spur gear 38A and spur gear 39. The roll 23 rotates. Further, when the forming servo motor 31B is rotated with the electromagnetic clutch 36B turned on, the pinion gear 32B, the spur gear 35B, the shaft 34B, the electromagnetic clutch 36B, the shaft 37B, the spur gear 38B, and the spur gear 39 are driven. As a result, the transfer roll 23 rotates. Accordingly, the stage 28A can be moved and the transfer roll 23 can be rotated by the molding servo motor 31A, and the stage 28B can be moved and the transfer roll 23 can be rotated by the molding servo motor 31B.

  Here, the shafts 34A and 34B and the spur gears 35A and 35B have a rotary ball spline structure as described above. That is, the shafts 34A and 34B can move up and down relatively with respect to the spur gears 35A and 35B. Therefore, by rotating the screw shaft 43a of the ball screw 43 by the lifting servo motor 45, as shown in FIG. 10, when the transfer roll 23 is raised, the spur gears 35A and 35B are not always raised and always have the same height. The shafts 34 </ b> A and 34 </ b> B, the electromagnetic clutches 36 </ b> A and 36 </ b> B, the shafts 37 </ b> A and 37 </ b> B, the spur gears 38 </ b> A and 38 </ b> B, and the spur gear 39 are raised together with the rack 22.

  Next, an example of a molding process for forming the uneven portion 9 on the light incident end surface 7a of the light guide plate 7 using the optical sheet processing apparatus 20 configured as described above will be described with reference to FIG. In the main forming step, two workers W are arranged on the front side of the optical sheet processing apparatus 20 (see FIG. 4). At this time, the transfer roll 23 is heated to a certain temperature (for example, 100 ° C. to 200 ° C.) by the induction coil 41 and the power supply unit 42.

  First, in the state where both the stage 28A on which the molded light guide plate 7 is placed and the stage 28B on which the light guide plate 7 before molding is placed are located on the front side of the optical sheet processing apparatus 20, the molding servo motor 31B. Is rotated in a predetermined direction to turn on the electromagnetic clutch 36B. The driving of the molding servo motor 31A is stopped, and the electromagnetic clutch 36A is OFF.

  Then, as shown in FIG. 11A, the stage 28B moves rearward while the transfer roll 23 rotates counterclockwise. At this time, a constant pressure (for example, 0.05 MPa to 50 MPa) is applied to the stage 28B so that the light incident end surface 7a of the light guide plate 7 placed on the stage 28B is pressed against the transfer surface 23a of the transfer roll 23 by the pressing cylinder 30B. Apply. As a result, the transfer uneven portion 19 of the transfer roll 23 is transferred to the light incident end surface 7a of the light guide plate 7 placed on the stage 28B. While the light guide plate 7 placed on the stage 28B is being molded in this way, the molded light guide plate 7 is taken out from the stage 28A.

  Next, driving of the molding servo motor 31B is stopped, and the electromagnetic clutch 36B is turned OFF. Then, as shown in FIG. 11B, the rotation of the transfer roll 23 stops and the stage 28B on which the molded light guide plate 7 is placed stops on the rear side of the optical sheet processing apparatus 20. In the meantime, a new light guide plate 7 is placed and placed on the stage 28A.

  Next, the stage 28A on which the new light guide plate 7 is placed is located on the front side of the optical sheet processing apparatus 20, and the stage 28B on which the molded light guide plate 7 is placed is located on the rear side of the optical sheet processing apparatus 20. In this state, the molding servo motor 31B is rotated in the opposite direction while the electromagnetic clutch 36B is turned off. Then, as shown in FIG. 11C, the stage 28B on which the molded light guide plate 7 is placed moves forward while the rotation of the transfer roll 23 is stopped. At this time, no pressure is applied to the stage 28B by the pressing cylinder 30B. When the stage 28B returns to the original position, the driving of the molding servo motor 31B is stopped. Meanwhile, the stage 28A on which the new light guide plate 7 is placed stands by at the same position.

  Next, with the stage 28A on which the new light guide plate 7 is placed and the stage 28B on which the molded light guide plate 7 is placed positioned on the front side of the optical sheet processing apparatus 20, the molding servo motor 31A is operated. The electromagnetic clutch 36A is turned ON by rotating in a predetermined direction.

  Then, as shown in FIG. 11D, the stage 28A moves to the rear side while the transfer roll 23 rotates clockwise. At this time, a constant pressure is applied to the stage 28A by the pressing cylinder 30A so that the light incident end surface 7a of the light guide plate 7 placed on the stage 28A is pressed against the transfer surface 23a of the transfer roll 23. As a result, the transfer uneven portion 19 of the transfer roll 23 is transferred to the light incident end surface 7a of the light guide plate 7 placed on the stage 28A. While the light guide plate 7 placed on the stage 28A is being molded in this way, the molded light guide plate 7 is taken out from the stage 28B.

  Next, the drive of the molding servo motor 31A is stopped, and the electromagnetic clutch 36A is turned OFF. Then, as shown in FIG. 11 (e), the rotation of the transfer roll 23 stops and the stage 28 </ b> A on which the molded light guide plate 7 is placed stops on the rear side of the optical sheet processing apparatus 20. Meanwhile, a new light guide plate 7 is placed and placed on the stage 28B.

  Next, the stage 28A on which the molded light guide plate 7 is placed is located on the rear side of the optical sheet processing apparatus 20, and the stage 28B on which the new light guide plate 7 is placed is located on the front side of the optical sheet processing apparatus 20. In the state where the electromagnetic clutch 36A is OFF, the molding servo motor 31A is rotated in the opposite direction.

  Then, as shown in FIG. 11F, the stage 28A on which the molded light guide plate 7 is placed moves to the front side while the rotation of the transfer roll 23 is stopped. At this time, no pressure is applied to the stage 28A by the pressing cylinder 30A. When the stage 28A returns to the original position, the driving of the molding servo motor 31A is stopped. Meanwhile, the stage 28B on which the new light guide plate 7 is placed stands by at the same position.

  In this way, in the main forming step, while the molded light guide plate 7 placed on the stage 28A is taken out and a new light guide plate 7 is put on the stage 28A, it is placed on the stage 28B. An uneven portion 9 is formed on the light incident end surface 7a of the placed light guide plate 7, the molded light guide plate 7 placed on the stage 28B is taken out, and a new light guide plate 7 is placed on the stage 28B. During the process, the uneven portion 9 is formed on the light incident end surface 7a of the light guide plate 7 placed on the stage 28A.

  At this time, the moving speed of the stages 28A and 28B is not necessarily constant. For example, when the plurality of LEDs 6 are arranged facing the light incident end surface 7 a of the light guide plate 7, the uneven portion 9 may be formed only on the light incident end surface 7 a around the LED 6. For this reason, when the transfer surface 23a of the transfer roll 23 and the light incident end surface 7a of the light guide plate 7 are pressed against each other, when the light incident end surface 7a at the position facing the LED 6 and the transfer surface 23a are in contact with each other, a desired uneven portion 9 is formed. When the stages 28A and 28B are moved at the transfer (molding) speed obtained, and the other light incident end surface 7a and the transfer surface 23a are in contact with each other, the stages 28A and 28B may be moved at a higher speed. Thereby, the processing tact of the light guide plate 7 can be improved. The light incident end surface 7a around the LED 6 indicates +1 mm from the width size of the LED 6 in the direction orthogonal to the thickness direction of the light guide plate 7.

  By the way, when the transfer uneven portion 19 provided on the transfer surface 23 a of the transfer roll 23 is thermally transferred to the light incident end surface 7 a of the light guide plate 7, the resin is thermally decomposed at the light guide plate 7, and the addition contained in the light guide plate 7. The additive may precipitate due to decomposition of the agent and adhere to the transfer surface 23 a of the transfer roll 23. Moreover, when the masking film is bonded to the main surface of the light guide plate 7, the glue component used for bonding the masking film adheres to the transfer surface 23 a of the transfer roll 23 by applying pressure during molding. Sometimes.

  Therefore, after the molding process is performed, if foreign substances such as additives and glue components adhere to the transfer surface 23a of the transfer roll 23, the transfer roll 23 is moved up and down by the lifting servo motor 45, and the transfer roll 23 is moved up and down. The portion of the transfer surface 23a in contact with the light incident end surface 7a of the light guide plate 7 is shifted, and the next molding process is performed using the clean transfer surface 23a to which no foreign matter is attached.

  As described above, in the present embodiment, the transfer roll 23 is heated and the transfer surface 23 a of the transfer roll 23 and the light incident end surface 7 a of the light guide plate 7 are pressed against each other to be provided on the transfer surface 23 a of the transfer roll 23. The uneven portion for transfer 19 is thermally transferred to the light incident end surface 7a of the light guide plate 7 so that the uneven portion 9 is formed on the light incident end surface 7a of the light guide plate 7. Chips are not generated unlike the case where the uneven portion 9 is formed on the light incident end surface 7a of the light guide plate 7. Accordingly, the chips are not attached to or mixed into the light guide plate 7, and the product quality can be stabilized.

  Further, in the present embodiment, means for raising and lowering the transfer roll 23 with respect to the stages 28A and 28B is provided, and when the transfer surface 23a of the transfer roll 23 is soiled, the soiled portion of the transfer surface 23a is located on the light guide plate 7. Since the transfer roll 23 is moved up and down so as to avoid contact with the light incident end surface 7a, the molding process can be continued quickly using the clean transfer surface 23a. Thereby, the quality of the product can be further stabilized. Further, for example, since it is not necessary to remove the transfer roll 23 and perform ultrasonic cleaning of the transfer roll 23, labor of the worker can be saved.

  At this time, since the induction coil 41 is built in the transfer roll 23 and the transfer roll 23 is heated by passing an electric current through the induction coil 41, the temperature is adjusted with oil and the transfer roll 23 is heated. In comparison, the temperature distribution in the roll axis direction of the transfer roll 23 can be made uniform. For example, when an oil heater roll having a diameter of 200 mm and a length of 300 mm is used, temperature unevenness of 3 ° C. to 5 ° C. occurs in the roll axis direction, but when using an electric heater roll of the same size, The temperature unevenness in the roll axis direction is within about ± 0.5 ° C. Thus, even when the contact position of the transfer surface 23a of the transfer roll 23 with the light incident end surface 7a of the light guide plate 7 is changed by moving the transfer roll 23 up and down, the transfer roll 23 with respect to the light incident end surface 7a of the light guide plate 7 is changed. The transfer accuracy of the transfer uneven portion 19 can be stabilized.

  The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the transfer roll 23 is moved up and down with respect to the stages 28A and 28B. However, the present invention is not particularly limited thereto, and the stage 28A and 28B can be moved up and down with respect to the transfer roll 23. The contact height position between the roll 23 and the light guide plate 7 may be changed.

  In the above embodiment, the transfer roll 23 is rotated by meshing the spur gears. However, the mechanism for rotating the transfer roll 23 is not particularly limited, and for example, a belt and a pulley may be used. good.

  Furthermore, in the above-described embodiment, the configuration is such that the transfer roll 23 is rotated by the forming servo motors 31A and 31B and the stages 28A and 28B are moved in the Y direction. Further, as means for moving the stages 28A and 28B, different motors may be used, and the motors may be driven synchronously.

  Here, when the light guide plate 7 and the transfer roll 23 are in contact with each other, if the rotational speed of the transfer roll 23 and the moving speed of the stages 28A and 28B are greatly shifted, the appearance of the light guide plate 7 is deteriorated. To do. For this reason, when the motor dedicated to the roll for rotating the transfer roll 23 is not installed, the diameter management of the transfer roll 23 is important. On the other hand, when a dedicated motor for rotating the transfer roll 23 is installed, the rotation speed of the motor can be adjusted in accordance with the diameter of the transfer roll 23. Can be prevented.

  In the above embodiment, the stages 28A and 28B are arranged so as to sandwich the transfer roll 23, but it goes without saying that the number of stages supporting the light guide plate 7 may be one as shown in FIG. At this time, the light incident end surface 7 a of the light guide plate 7 may be pressed against the transfer surface 23 a of the transfer roll 23 as described above, but the transfer surface 23 a of the transfer roll 23 is pressed against the light incident end surface 7 a of the light guide plate 7. May be. Further, the number of light guide plates 7 supported on the stage is not limited to one, and may be a plurality.

  Furthermore, in the above embodiment, the roll shaft 23b of the transfer roll 23 extends in the apparatus vertical direction (Z direction). However, in the optical sheet processing apparatus of the present invention, the roll shaft 23b of the transfer roll 23 is in the horizontal direction (X direction). Alternatively, the present invention can be applied to those extending in the Y direction.

  Moreover, although the said embodiment forms the uneven | corrugated | grooved part 9 in the light-incidence end surface 7a of the light-guide plate 7 comprised in the backlight unit 3 of the liquid crystal display device 1 used for a liquid crystal television, the optical of this invention The sheet processing apparatus and method can be applied to, for example, an optical sheet forming process as a light guide plate for illumination or decoration.

  DESCRIPTION OF SYMBOLS 7 ... Light guide plate (optical sheet), 7a ... Light-incidence end surface, 9 ... Uneven part, 20 ... Optical sheet processing apparatus, 22 ... Rack (2nd moving means), 23 ... Transfer roll, 23a ... Outer peripheral surface (transfer surface) , 23b ... roll shaft, 26A, 26B ... stage base (first moving means), 27A, 27B ... guide rail (first moving means), 28A, 28B ... stage, 30A, 30B ... pressing cylinder (pressure applying means), 31A, 31B ... molding servo motor (rotating means, first moving means), 32A, 32B ... pinion gear (rotating means, first moving means), 33A, 33B ... rack gear (first moving means), 34A, 34B ... Shaft (rotating means), 35A, 35B ... spur gear (rotating means), 36A, 36B ... electromagnetic clutch (rotating means), 37A, 37B ... shaft (rotating means), 38A, 38 ... spur gear (rotating means), 39 ... spur gear (rotating means), 41 ... induction coil (heating means), 42 ... power supply (heating means), 43 ... ball screw (second moving means), 44 ... main lifting body (Second moving means), 45... Lift servo motor (second moving means), 46... Linear guide (second moving means), 47 .. auxiliary lifting body (second moving means).

Claims (4)

An optical sheet processing apparatus for forming an uneven portion on a light incident end face of an optical sheet made of a thermoplastic resin,
A stage for supporting the optical sheet;
A metal transfer roll having a transfer surface for imparting the concavo-convex portion to the light incident end surface of the optical sheet supported by the stage;
Heating means for heating the transfer roll;
Pressure applying means for applying pressure so as to press the transfer surface and the light incident end surfaces;
A rotating means for rotating the transfer roll;
First moving means for moving the stage relative to the transfer roll in the formation direction of the concavo-convex portion;
An optical sheet processing apparatus comprising: a second moving unit that moves the transfer roll relative to the stage in a roll axis direction of the transfer roll.   The optical sheet processing apparatus according to claim 1, wherein a masking film is bonded to a main surface of the optical sheet.   The optical sheet processing apparatus according to claim 1, wherein the heating unit includes an induction coil provided on the transfer roll and a power supply unit that supplies a current to the induction coil. An optical sheet processing method for forming a concavo-convex portion on a light incident end face of an optical sheet made of a thermoplastic resin,
A preparation step of preparing the optical sheet processing apparatus according to any one of claims 1 to 3,
While the transfer roll is heated and the pressure is applied so as to press the transfer surface and the light incident end faces, the stage is formed with respect to the transfer roll while rotating the transfer roll. A forming step of forming the concavo-convex portion on the light incident end face by moving in a direction relatively;
After carrying out the forming step, when the foreign matter adheres to the transfer surface, the transfer roll is arranged so as to avoid the light incident end face coming into contact with the foreign matter attachment location on the transfer surface. An avoiding step of moving the transfer roll relative to the stage in the roll axis direction of the transfer roll.

Images