JP5705895B2 - Optical sheet manufacturing method and surface light source device manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a surface light source device.

  A transmissive image display device such as a liquid crystal display device generally has a surface light source device as a backlight. The surface light source device includes a so-called direct type backlight. In the direct type backlight, since the light source is directly under the liquid crystal panel, the image of the light source may be seen through the screen as it is. Therefore, in the direct type backlight, an optical member called a diffusion plate is provided. The diffusing plate is a member for making light from the light source uniform. For example, the surface of the diffusing plate is printed in a predetermined pattern with ink having light diffusing properties. (For example, patent document 1).

  Further, the surface light source device includes an edge light type surface light source device having a light guide plate and having a light source provided along an end surface thereof. As a light guide plate used in such a surface light source device, there is a light guide plate in which light scattering dots are provided on one surface of a light guide plate base material constituting the light guide plate. In this light guide plate, light incident from the end face of the light guide plate travels while being totally reflected in the light guide plate base material. The light scatters when entering a light scattering dot provided on one surface of the light guide plate, and is emitted from the other surface of the light guide plate with an angle component equal to or greater than the critical angle. Such light scattering dots are formed by a method such as printing (for example, Patent Document 2).

  Such an optical sheet such as a diffusion plate and a light guide plate is cut into a desired size (a size when incorporated in a surface light source device) after a continuous resin sheet is manufactured by, for example, an extrusion molding method. And the printing etc. which provide a spreading | diffusion function and a reflective function are performed with respect to the resin sheet cut | disconnected by the target size. The optical sheet thus manufactured is transported to a place where the surface light source device is assembled and assembled together with other parts constituting the surface light source device.

JP 2010-128447 A Japanese Patent Laid-Open No. 09-068614

  However, in the above conventional method of manufacturing a surface light source device, an optical sheet that can be incorporated into the surface light source device is manufactured in the optical sheet manufacturing process and transported to the surface light source device assembly process. The end face of the optical sheet may be damaged. In order to prevent this damage, it is necessary to strictly pack the optical sheet to protect the end face, and labor is required for the packing and unpacking.

  Therefore, a main object of the present invention is to provide a method of manufacturing a surface light source device that can improve productivity.

  The method of manufacturing a surface light source device according to one aspect of the present invention includes a pattern forming step of forming a functional pattern in which functional portions having a reflection function or a diffusion function are arranged according to a predetermined rule on at least one surface of a resin sheet; The functional pattern is formed in the transporting step of transporting the resin sheet on which the functional pattern is formed from the first place where the pattern forming process is performed to the second place, and in the second place transported in the transporting process. A precision cutting step of forming an optical sheet by precisely cutting the resin sheet into a target size, and an assembly step of manufacturing a surface light source device by incorporating at least the optical sheet and the light source device.

  In this method of manufacturing the surface light source device, the pattern forming process and the precision cutting process sandwich the process of transporting the resin sheet on which the functional pattern is formed to the place where the precision cutting process is performed, and are interrupted between these processes. The The precision cutting process and the assembling process are continuously executed without interruption between these processes. Here, when the method for manufacturing the conventional surface light source device and the method for manufacturing the surface light source device of the present invention are compared, the former is transported with an optical sheet precisely cut to a desired size, whereas the latter is The optical sheet in a state before being precisely cut to a target size is conveyed. In the method of manufacturing the surface light source device of the present invention, even if the end surface of the optical sheet having a size larger than the target size is damaged during conveyance, the damaged portion is cut out in the precision cutting step. That is, a new end face is formed in the precision cutting process. The optical sheet on which the new end surface is formed is continuously incorporated into the surface light source device as it is. Therefore, in order to prevent damage to the end face of the optical sheet precisely cut to the desired size, packaging for protecting the end face of the optical sheet, which has been performed in the above-described conventional method of manufacturing a surface light source device, and Unpacking in the assembly process can be eliminated. As a result, productivity can be improved.

  You may further include the sticking process of sticking a protective film on the surface in which a functional pattern was formed, and the surface on the opposite side to the surface in which the functional pattern was formed between a pattern formation process and a conveyance process. If a protective film is stuck on the surface on which the functional pattern is formed, it is possible to prevent the surface on which the functional pattern is formed from being damaged during transportation. If a protective film is affixed to the surface opposite to the surface on which the functional pattern is formed, it is possible to prevent the surface opposite to the surface on which the functional pattern is formed from being damaged during conveyance.

  In the precision cutting step, the resin sheet on which the functional pattern is formed may be precisely cut out to a desired size, and at the same time, an uneven shape extending in the thickness direction of the resin sheet may be processed on the end surface.

  In the conventional method of manufacturing a surface light source device, when an optical sheet having an uneven surface is conveyed to the assembly process of the surface light source device, strict packaging is required to protect the end surface. It took time to work. In this manufacturing method, since the precision cutting process is performed at the time when the assembly process of the surface light source device is performed, it is possible to eliminate packaging for preventing damage to the end surface due to conveyance.

  The manufacturing method includes a resin sheet molding process for molding a resin into a continuous resin sheet in one direction, and a continuous resin sheet continuously fed out from the resin sheet molding process larger than the target size. A rough cutting step of cutting into a roughly cut sheet of a size, and the resin sheet may be the rough cut sheet obtained by the rough cutting step.

  In the precision cutting process, the resin sheet on which the functional pattern is formed may be precisely cut out to a desired size by irradiating laser light, or the functional pattern is formed using a punching device that punches the resin sheet. The resin sheet may be precisely cut out to a desired size.

  According to the method for manufacturing a surface light source device of the present invention, productivity can be improved.

1 is an overall schematic view of a manufacturing apparatus used in an embodiment. It is drawing which showed the processing state of the resin sheet in each process of one Embodiment. It is a flowchart which shows the process of one Embodiment. It is each drawing for demonstrating other embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent element, and the overlapping description is abbreviate | omitted. Further, the dimensional ratios in the drawings do not necessarily match those described. Further, in the description, words indicating directions such as “up” and “down” are convenient words based on the state shown in the drawings.

  FIG. 1 is an overall schematic diagram of a manufacturing apparatus used in an embodiment. FIG. 2 is a view showing a processed state of the resin sheet in each step of the embodiment. First, an apparatus for manufacturing a light guide plate (optical sheet) will be described. As shown in FIG. 1, an apparatus 1 that manufactures a surface light source device (hereinafter referred to as “surface light source device manufacturing apparatus 1”) includes a resin sheet molding unit 10 and a rough cutting unit that are installed at a first location P1. 20, the pattern forming unit 30, the precision cutting unit 50 and the assembling unit 60 installed at the second location P2, and the transport unit 40 installed between the first location P1 and the second location P2. And.

  First, the resin sheet shaping | molding part 10, the rough cutting part 20, and the pattern formation part 30 installed in the 1st place P1 are demonstrated. The resin sheet molding part 10 is a part that molds a continuous resin sheet 80 that is a sheet-like resin continuous in one direction (feeding direction). The resin sheet molding unit 10 may be an extrusion molding apparatus that molds the continuous resin sheet 80 by extruding from a molten thermoplastic resin. The extrusion molding apparatus extrudes a molten resin supplied from the extruder 12 into a sheet shape, a resin inlet 11 for introducing a thermoplastic resin as a raw material, an extruder 12 for heating and melting the thermoplastic resin. And a first pressing roll 14, a second pressing roll 15, and a third pressing roll 16 for forming a sheet-like continuous resin sheet 80 extruded from the die 13.

  Examples of the resin include acrylic resin, styrene resin, polymethyl methacrylate (PMMA) resin, polystyrene (PS) resin, MS (methyl methacrylate-styrene copolymer) resin, polycarbonate resin, AS (acrylonitrile-styrene). Copolymer) resin, cycloolefin resin, polyethylene resin, polypropylene resin, and polyethylene terephthalate resin. In addition, additives such as a light diffusing agent, an ultraviolet absorber, a heat stabilizer, and a photopolymerization stabilizer can be added to these resins.

  The rough cutting part 20 is disposed between the resin sheet molding part 10 and the pattern forming part 30. The rough cutting part 20 is a part that cuts the continuous resin sheet 80 continuously sent out from the resin sheet molding part 10 into a rough cut sheet 95 having a size larger than the target size. Examples of the rough cutting unit 20 include a laser cutting device using laser light. As the laser light source of the laser cutting device, for example, a carbon dioxide laser, a YAG laser, an excimer laser or the like is preferably used. Further, the rough cutting unit 20 may be a cutting machine, a rotary blade, a shearing machine, or the like.

  The pattern forming unit 30 has predetermined light scattering dots (functional unit having a reflection function) 81 that diffusely reflect light on one surface 95a of the roughly cut sheet 95 that is continuously sent out from the resin sheet molding unit 10. This is a portion for printing (forming) a dot pattern (functional pattern) 82 arranged according to the above rule.

  The pattern forming unit 30 can use an ink jet device that prints the dot pattern 82 by ejecting droplet-like light-reflective ink onto one surface 95 a of the roughly cut sheet 95. The ink jet apparatus can be configured, for example, such that droplet-like ink ejected from a plurality of nozzles is ejected simultaneously in the entire width direction of the roughly cut sheet 95. Preferably, the predetermined dot pattern 82 is printed by ejecting ink while continuously moving the roughly cut sheet 95 at a constant speed. Further, the ink is ejected in a state where the rough cut sheet 95 is stopped, and the rough cut sheet 95 is moved to the next printing position and then stopped (intermittent conveyance). A dot pattern 82 may be printed. As shown in FIG. 2, the pattern forming unit 30 has a predetermined region 90a precisely cut to a target size in the precision cutting unit 50, in other words, a product region precisely cut to the size of a light guide plate as one product. The dot pattern 82 is printed.

  The ink ejected to the roughly cut sheet 95 may be any ink that forms light scattering dots by curing or drying, and for example, ultraviolet curable ink, water-based ink, or solvent ink is used. Among these, ultraviolet curable ink and water-based ink are preferable from the viewpoint of easy environmental measures. When ultraviolet curable ink is used, it is cured by a UV lamp or the like. When water-based ink or solvent ink is used, the ink is dried by a drying device to form light scattering dots. When an ink jet apparatus is used as the pattern forming unit 30, a plasma processing unit that performs plasma processing may be provided upstream of the pattern forming unit 30.

  Next, the conveyance part 40 installed in the 1st place P1 and the 2nd place P2 is demonstrated. In other words, the transport unit 40 is disposed between the pattern forming unit 30 and the precision cutting unit 50. The conveyance part 40 is a part which conveys the rough cut sheet 95 in which the dot pattern 82 manufactured in the 1st place P1 was formed to the 2nd place P2. Between the first place P1 and the second place P2, the rough cut sheet 95 on which the dot pattern 82 is formed may be transported through a human hand, or a transport machine such as a transport robot. However, the rough cut sheet 95 on which the dot pattern 82 is formed may be conveyed. That is, it is only necessary to have a means for transporting between the first place P1 and the second place P2 that are physically separated. Here, “physically separated” means a state in which so-called lines are discontinuous (off), and distance is not a problem. The first place P1 and the second place P2 may be in the same room or the same site.

  First, the precision cutting part 50 and the assembly part 60 installed in the 2nd place P2 are demonstrated. The precision cutting unit 50 is a part that forms the light guide plate 90 by precisely cutting the rough cut sheet 95 on which the dot pattern 82 conveyed by the conveying unit 40 is formed to a target size. The precision cutting unit 50 uses a cutting device that does not require finishing processing of the cut surface after cutting, in other words, a cutting device that performs mirror surface processing or serration processing (see FIG. 4A) at the same time as cutting. Is desirable. Such a precision cutting unit 50 includes a laser cutting device using laser light. As the laser light source of the laser cutting device, for example, a carbon dioxide laser, a YAG laser, an excimer laser or the like is preferably used.

  The size when cutting out from the roughly cut sheet 95 is selected so as to match the screen size of the target surface light source device. The size is 120 mm or more in the short side direction and 220 mm or more in the long side direction, 1250 mm in the short side direction, and 2220 mm or less in the long side direction. Further, the length of the diagonal line when precisely cut out from the continuous resin sheet 80 is 25 cm or more and 250 cm or less.

  The assembly unit 60 is a part that manufactures the surface light source device 73 by incorporating at least the light guide plate 90, the light source device 71, and a frame that is an example of a component that connects the light guide plate 90 and the light source device 71. In the assembling unit 60, the light guide plate 90 conveyed from the precision cutting unit 50 is grasped by the grasping hand 61 and moved to the position where the frame is disposed. Further, the light source device 71 is grasped by the grasping hand 61 and moved to the position where the frame is arranged. Then, the light guide plate 90 and the light source device 71 are fixed via a frame and assembled as a surface light source device 73.

  In the surface light source device manufacturing apparatus 1, the continuous resin sheet 80 and the rough cut sheet 95 from the resin sheet molding unit 10 to the pattern forming unit 30 are transported, and the rough cut sheet from the precision cutting unit 50 to the assembly unit 60. 95 and the light guide plate 90 are transported by a transport device. Examples of the transfer device include a transfer roller, a table shuttle, a belt conveyor, a transfer roller, and an air levitation transfer device.

  Next, an example of the manufacturing process of the light guide plate 90 will be described. FIG. 3 is a flowchart showing the steps of one embodiment. As shown in FIG. 3, the manufacturing process of the light guide plate in the present embodiment includes a resin sheet forming step S1, a rough cutting step S2, a pattern forming step S3, a conveying step S4, and a conveying step S4. A precision cutting step S5 and an assembling step S6 performed at the second place P2. Hereinafter, each process is demonstrated in order.

  First, a process performed at the first place P1 will be described. In the resin sheet molding step S1, the continuous resin sheet 80 is molded. Examples of the method of forming the continuous resin sheet 80 include an extrusion method of forming a continuous resin sheet by extruding a molten thermoplastic resin. In the extrusion molding method, for example, an acrylic resin is melt-kneaded and extruded as a thermoplastic resin, and is sandwiched and pressed between various pressing rolls. Thereby, the continuous resin sheet 80 of predetermined thickness is shape | molded. The thickness of the continuous resin sheet 80 is from 0.1 mm to 2.0 mm, preferably from 0.1 mm to 1.0 mm, and more preferably from 0.2 mm to 0.7 mm.

  The rough cutting step S2 is performed between the resin sheet forming step S1 and the pattern forming step S3. In the rough cutting step S2, the continuous resin sheet 80 delivered from the resin sheet forming step S1 is cut into a rough cut sheet 95 having a size larger than the target size (see FIG. 2). Examples of the method of cutting the continuous resin sheet 80 into the roughly cut sheet 95 include a method of cutting the continuous resin sheet 80 using laser light. In addition, an example of a method of cutting the roughly cut sheet 95 from the continuous resin sheet 80 may be a method using a cutting machine, a rotary blade, a shearing machine, or the like.

  In the pattern forming step S3, a dot pattern in which light scattering dots (functional portions) 81 having a reflecting function are arranged on a surface 95a of the rough cut sheet 95 sent out from the rough cutting step S2 according to a predetermined rule ( A functional pattern 82 is printed (formed). Examples of the dot pattern 82 arranged according to a predetermined rule include a dot pattern in which the shape of the light scattering dots 81 increases as the distance from the end surface serving as the incident surface increases, and a dot pattern in which the density of the light scattering dots 81 increases. included. Examples of the method for printing the dot pattern 82 include an inkjet method in which droplet-like ink ejected from a nozzle is ejected onto the printing surface of the continuous resin sheet 80.

  In the transport process S4, the roughly cut sheet 95 on which the functional pattern 82 is formed is transported from the first place P1 to a second place P2 where a precision cutting process S5 described later is performed. Since the transport process S4 is performed between the pattern formation process S3 and the precision cutting process S5, it is interrupted between these processes. That is, the continuous resin sheet on which the functional pattern is formed is not cut into a target size immediately after being cut into a size larger than the target size, and is not conveyed to the assembly process.

  Next, a process performed at the second place P2 will be described. In the precision cutting step S5, the light-cutting plate (optical sheet) 90 is formed by precisely cutting the rough cut sheet 95 on which the dot pattern 82 conveyed in the precision cutting step S5 is printed into a desired size. The An example of a method of precisely cutting the roughly cut sheet 95 to a target size includes a method of cutting the roughly cut sheet 95 using laser light. Moreover, as a method of cutting out the continuous resin sheet 80, a cutting method that does not require finishing processing of the cut surface after cutting, in other words, a method in which mirror processing is performed simultaneously with cutting, or as shown in FIG. In addition, it is desirable to perform serration processing (processing for forming a concavo-convex shape extending in the thickness direction of the continuous resin sheet on the surface to be the end surface) simultaneously with the cutting.

  In the assembly step S6, at least the light guide plate 90, the light source device 71, and a frame that is an example of a component that connects the light guide plate 90 and the light source device 71 are incorporated, and the surface light source device 73 is manufactured. Then, the process of manufacturing a transmissive | pervious image display apparatus by incorporating a surface light source device, a liquid crystal display device, an optical film etc. in a flame | frame may be continued.

  Next, the effect of the manufacturing method of the said light-guide plate is demonstrated. In the method of manufacturing the surface light source device, the pattern forming step S3 and the precision cutting step S5 are transporting steps of transporting the roughly cut sheet 95 on which the dot pattern 82 is formed from the first place P1 to the second place P2. Since S4 is sandwiched, it is interrupted between these processes. The precision cutting step S5 and the assembling step S6 are continuously executed without interruption between these steps. Here, when comparing the manufacturing method of the conventional surface light source device and the manufacturing method of the surface light source device of the above embodiment, the former is transported an optical sheet precisely cut to a desired size, whereas the latter The optical sheet (in this case, the roughly cut sheet 95) before being precisely cut to the target size is conveyed. In the method of manufacturing the surface light source device of the above embodiment, even if the end surface of the optical sheet (here, the rough cut sheet 95) larger than the target size is damaged during conveyance, the damaged portion is precise. Cut out in the cutting step S5. That is, a new end face is formed in the precision cutting step S5. The optical sheet (here, the light guide plate 90) on which the new end surface is formed is continuously incorporated into the surface light source device 73 as it is. Therefore, in order to prevent damage to the end face of the optical sheet precisely cut to the desired size, packaging for protecting the end face of the optical sheet, which has been performed in the above-described conventional method of manufacturing a surface light source device, and Unpacking in the assembly process can be eliminated. As a result, productivity can be improved.

  As mentioned above, although one Embodiment of this invention was described, this invention is not restricted to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention.

  In the said embodiment, although the extrusion molding method was mentioned as an example of the method of shape | molding the continuous resin sheet 80, and the example which shape | molds the continuous resin sheet 80 using an extrusion molding apparatus as an example was demonstrated, this invention is limited to this. Is not to be done. For example, it is possible to use a casting method in which a raw material is poured into a template and polymerized. Examples of the cast manufacturing method include a continuous cast plate manufacturing method using an endless belt made of a continuous stainless steel plate or the like. Specifically, a polymerization initiator is provided in a space formed by the opposing surfaces of a pair of endless belts that run opposite each other at a predetermined interval and two gaskets that run following the running of the endless belt. Examples include a method of injecting a dissolved polymerizable raw material, polymerizing and curing the polymerizable raw material, and peeling and taking out the formed plate-like polymer from the endless belt.

  In the above embodiment, as a method of printing the dot pattern 82 on one surface 95a of the rough cut sheet 95, the ink jet method, and as an example, one surface 95a of the rough cut sheet 95 using an ink jet apparatus. Although an example in which the dot pattern 82 is printed is described above, the present invention is not limited to this.

  For example, an example of a method for printing the dot pattern 82 includes a screen printing method. In the pattern forming step S3, a method of forming a functional pattern in which functional portions having a reflection function or a diffusion function are arranged according to a predetermined rule is a method of forming a functional pattern composed of a plurality of concave portions by irradiating laser light. And a method of forming a functional pattern including a plurality of concave portions or convex portions by pressing a stamper having fine irregularities formed thereon.

  In the above embodiment, a method of cutting using a laser beam as a cutting method of the roughly cut sheet 95 on which the dot pattern 82 is printed, and an example of cutting the continuous resin sheet 80 using a laser cutting device as an example thereof However, the present invention is not limited to this. For example, the light guide plate (optical sheet) 90 may be formed by a method of punching the roughly cut sheet sheet 95 on which the dot pattern 82 is printed in accordance with the shape of the light guide plate 90. Examples of the punching die for punching the rough cut sheet 95 into a desired shape include a punching device equipped with a Thomson blade or the like.

  In the above embodiment, in the resin sheet molding step S1, an example in which a shape such as unevenness is not provided on the surface on the light emitting plate 90 side, that is, the first to first in the extrusion molding apparatus as the resin sheet molding unit 10 is provided. Although an example in which unevenness is not formed on any peripheral surface of the three pressing rolls 14, 15, 16 has been described, the present invention is not limited to this. For example, in the resin sheet molding step S <b> 1, a ridge or the like that extends in one direction may be formed on the surface of the continuous resin sheet 80 on the side that becomes the emission surface. In this case, it is possible to form a ridge or the like by providing irregularities on the peripheral surface of the second pressing roll 14 in the extrusion molding apparatus. Similarly, an embossed surface having a diffusion function can be formed.

  Further, in the above-described embodiment, in the pattern forming step S3, the region 90a that is precisely cut out to one target size is formed in the width direction of the roughly cut sheet 95, and the dot pattern 82 is printed in the region 90a. Although described with an example, the present invention is not limited to this. For example, in the width direction of the roughly cut sheet 95, two regions 90a that are precisely cut out to a target size are formed (see FIG. 4B), or three or more regions 90a may be formed. Further, a different dot pattern 82 may be printed for each region 90a.

  In conveyance process S4 of the above-mentioned embodiment, dot pattern 82 was printed in the state where a protective film was pasted on at least one side of the surface to be printed and the surface opposite to the surface to be printed (non-printing surface). The rough cut sheet 95 may be conveyed. That is, you may provide the process of bonding a protective film before conveyance process S4. Thereby, the damage of the printing surface and non-printing surface at the time of conveyance can be prevented. Moreover, it is good also as a structure provided with the process of apply | coating an antistatic liquid in the downstream process of the sticking process which sticks a protective film in this case.

  Moreover, in the said embodiment, the example which manufactures the light-guide plate used for what is called an edge-type backlight, ie, the dot pattern 82 which consists of the light-scattering dot 81 which has a reflective function in one side 95a of the rough cut sheet 95. However, the present invention is not limited to this. For example, in the present invention, a diffusion plate (optical sheet) used for a so-called direct type backlight can be formed. In this case, in the pattern forming step S3, a dot pattern (functional pattern) composed of diffusing dots (functional part having a diffusing function) is used on one surface 95a of the roughly cut sheet 95, using light diffusing ink or the like. ). Even in the case of manufacturing such a diffusion plate, productivity can be improved. Note that the diffuser plate manufactured in this way may be arranged so that the surface on which the dot pattern is printed becomes the exit surface, or may be arranged so that it becomes the entrance surface. However, it is preferable to arrange so that the surface on which the dot pattern is printed becomes the exit surface.

  DESCRIPTION OF SYMBOLS 1 ... Surface light source device manufacturing apparatus, 10 ... Resin sheet molding part, 11 ... Resin insertion port, 12 ... Extruder, 13 ... Die, 14 ... 1st press roll, 15 ... 2nd press roll, 16 ... 3rd press roll , 20 ... Rough cutting part, 30 ... Pattern forming part, 40 ... Conveying part, 50 ... Precision cutting part, 60 ... Assembly part, 61 ... Holding hand, 71 ... Light source device, 73 ... Surface light source device, 80 ... Continuous resin sheet , 81 ... Light scattering dots (functional part), 82 ... Dot pattern (functional pattern), 90 ... Light guide plate (optical sheet), 90a ... Area precisely cut to the desired size (product area), 95 ... Roughly cut sheet Leaf sheet (resin sheet), S1 ... resin sheet forming step, S2 ... rough cutting step, S3 ... pattern forming step, S4 ... conveying step, S5 ... precision cutting step, S6 ... assembly step, P1 ... first place, P2 ... second place.

Claims (6)

A pattern forming step of forming a functional pattern in which functional portions having a reflection function or a diffusion function are arranged according to a predetermined rule on at least one surface of the resin sheet;
A conveying step of conveying the resin sheet on which the functional pattern is formed from a first place where the pattern forming step is performed;
A precision cutting step of forming an optical sheet by precisely cutting the resin sheet on which the functional pattern is formed into a target size at the second location conveyed in the conveyance step ,
In the precision cutting step, the resin sheet on which the functional pattern is formed is precisely cut out to a desired size, and at the same time, an uneven surface extending in the thickness direction of the resin sheet is processed on the end surface . Production method. A resin sheet molding step of molding the resin into a sheet-like continuous resin sheet continuous in one direction;
A rough cutting step of cutting the continuous resin sheet continuously fed out from the resin sheet molding step into a coarsely cut sheet having a size larger than a target size;
A pattern forming step of forming a functional pattern in which functional portions having a reflection function or a diffusion function are arranged according to a predetermined rule on at least one surface of the rough cut sheet obtained by the rough cutting step ;
A transporting step of transporting the roughly cut sheet having the functional pattern formed thereon from a first place to which the pattern forming step is performed;
A precision cutting step of forming an optical sheet by precisely cutting the rough cut sheet having the functional pattern formed therein into a target size at the second location conveyed in the conveyance step;
A method for producing an optical sheet , comprising: The method further includes an attaching step of attaching a protective film to at least one of the surface on which the functional pattern is formed and the surface opposite to the surface on which the functional pattern is formed between the pattern forming step and the transporting step. The manufacturing method according to claim 1 or 2 . The manufacturing method according to any one of claims 1 to 3 , wherein, in the precision cutting step, the resin sheet on which the functional pattern is formed is precisely cut into a target size by irradiating a laser beam. The manufacturing according to any one of claims 1 to 4 , wherein, in the precision cutting step, the resin sheet on which the functional pattern is formed is precisely cut into a target size using a punching device that punches the resin sheet. Method. The manufacturing method of a surface light source device including the assembly process of incorporating the optical sheet and light source device which are obtained by the manufacturing method as described in any one of Claims 1-5, and manufacturing a surface light source device.

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