TW201439619A - Manufacturing method for optical sheet and manufacturing method for planar light source device - Google Patents

Abstract

This manufacturing method for an optical sheet (90) includes: a functional structure formation step (S3) wherein one or more functional structures (82) having a reflection function or a diffusion function are formed on at least one surface (95a) of a resin sheet (95); and a precision cutting step (S5) wherein one or more optical sheets (90) of an intended size are obtained by cutting the resin sheet, on which the one or more functional structures have been formed, by irradiating the resin sheet with a laser beam or by using a punching device.

Description

Optical sheet manufacturing method and method of manufacturing surface light source device

The present invention relates to a method of producing an optical sheet and a method of manufacturing the surface light source device.

A transmissive image display device such as a liquid crystal display device generally includes a surface light source device as a backlight. Among the surface light source devices, there is a so-called direct type backlight. In the direct type backlight, since the light source is located directly under the liquid crystal panel, the image of the light source can be seen through the screen in this state. Therefore, in the direct type backlight, an optical member such as a light diffusing plate is provided. The light diffusing plate is a member for homogenizing light from a light source, for example, printing a surface of a light diffusing plate in a specific pattern by an ink having light diffusibility (for example, Japanese Patent Laid-Open Publication No. 2010-128447 (Patent No.) Literature 1)).

Further, in the surface light source device, there is a surface light source device having a light guide plate and an edge light method in which a light source is provided along an end surface thereof. In the light guide plate used in such a surface light source device, a light guide plate provided with a light scattering point on one main surface of a light guide plate substrate constituting the light guide plate is present. In the light guide plate, light incident from the end surface of the light guide plate travels while being totally reflected on the substrate of the light guide plate. The light is incident on a light scattering point provided on one main surface of the light guide plate, and is scattered to become an angular component of a critical angle or more and is emitted from the other main surface of the light guide plate. Such a light-scattering point is formed by a method such as printing (for example, Japanese Patent Laid-Open Publication No. Hei 09-068614 (Patent Document 2)).

The optical sheet such as the light-diffusing sheet and the light-guide plate is cut into a target size after the continuous resin sheet is produced by an extrusion molding method or the like (the ruler is assembled to the surface light source device). Inch). Then, the end face is mechanically ground using a cutting machine. In this manner, the resin sheet which is cut to the target size and whose end surface is polished is subjected to printing or the like for imparting a diffusion function or a reflection function. The optical sheet manufactured in this manner is transported to a place where the surface light source device is assembled, and assembled together with other components constituting the surface light source device.

However, in the above-described method of manufacturing a surface light source device, an optical sheet which can be directly assembled to the surface light source device is manufactured in the optical sheet manufacturing step, and is transported to the surface light source device assembly step, and thus In the transfer step, the end face of the optical sheet is damaged. In order to prevent this damage, it is necessary to strictly carry out the packing for holding the end faces of the optical sheets, which requires labor.

Accordingly, it is a primary object of the present invention to provide a method for producing an optical sheet which can improve the productivity of a surface light source device and a method for producing a surface light source device which can improve productivity.

In order to achieve the above object, the present invention provides the following means.

<1>

A method for producing an optical sheet, comprising: a functional structure forming step of forming at least one side of a resin sheet to form one or more functional structures having a reflecting function or a diffusing function; and a precise cutting step The optical sheet having the above-described functional structure is cut by irradiating laser light or by using a punching device to obtain one or more optical sheets of a target size.

<2>

The method for producing an optical sheet according to the above <1>, wherein the functional structure forming step and the transferring step further include a bonding step of forming a surface of the functional structure and forming the functional structure. The protective film is bonded to at least one of the faces on the opposite side.

<3>

The method of producing an optical sheet according to the above <1>, wherein the resin sheet having one or more of the functional structures is cut in the precision cutting step to obtain one or more targets. At the same time as the size of the optical sheet, the end surface of the optical sheet is provided with a concavo-convex shape.

<4>

The method for producing an optical sheet according to any one of the above-mentioned items, further comprising: a resin sheet forming step of forming a resin into a continuous resin sheet in a continuous direction in a sheet direction; And a rough cutting step of cutting the continuous resin sheet continuously fed from the resin sheet forming step to obtain a rough-cut single sheet having a size larger than the target size; and the resin sheet is obtained by The above-mentioned rough cut single sheet obtained by the above coarse cutting step.

<5>

The method for producing an optical sheet according to any one of the above-mentioned items, wherein the functional structure forming step and the transferring step further comprise: a packing step of performing the resin sheet a packing step of conveying the resin sheet which has been bundled, and a step of unpacking the resin sheet which is carried by the package.

<6>

A method of manufacturing a surface light source device, comprising the steps of: manufacturing an optical sheet by the method for producing an optical sheet according to any one of the above <1> to <5>; and assembling the optical sheet and the light source device The steps of manufacturing a surface light source device.

In the method for producing an optical sheet according to the above <1>, by irradiating laser light or borrowing Since the precision cutting step is performed by using the punching device, it is not necessary to grind the end face of the obtained optical sheet. Therefore, even if the precise cutting step is carried out after the functional structure forming step, the obtained optical sheet can be directly used as an article. Therefore, after the functional structure is formed by the functional structure forming step and before the precise cutting step, the resin sheet having the functional structure can be conveyed without performing strict packing. On the other hand, in the above-described method for producing an optical sheet, it is necessary to polish the end face before the functional structure is formed, so that the precise cutting step cannot be performed after the functional structure forming step. Therefore, when transporting a resin sheet (optical sheet) having a functional structure, in order to protect the end surface, it is necessary to carry out strict packing, which requires considerable labor for unpacking. In the method for producing an optical sheet of the present invention, the resin sheet having the functional structure can be transported without performing strict packing, so that labor required for the baling and unbundling can be reduced, and productivity can be improved.

In the method for producing an optical sheet according to the above <2>, when the protective film is attached to the surface on which the functional structure is formed, it is possible to prevent the surface on which the functional structure is formed from being damaged during transportation. When a protective film is attached to the surface opposite to the surface on which the functional structure is formed, it is possible to prevent the surface on the opposite side to the surface on which the functional structure is formed from being damaged during transportation.

In the above-described method for producing an optical sheet, in the case where the optical sheet having the end surface of the concave-convex shape is conveyed to the surface light source device, it is necessary to perform a strict packing for protecting the end surface. needs time. In the method for producing an optical sheet according to the above <3>, the precise cutting step can be performed after the conveyance or the like, so that the labor required for the packaging and the unbundling to prevent the damage of the end surface caused by the conveyance can be reduced.

According to the method for producing an optical sheet of the present invention and the method for producing a surface light source device, productivity can be improved.

1‧‧‧ surface light source device manufacturing device

10‧‧‧Resin sheet forming department

11‧‧‧Resin input

12‧‧‧Extrusion machine

13‧‧‧Mold

14‧‧‧1st pressing roller

15‧‧‧2nd pressing roller

16‧‧‧3rd pressing roller

20‧‧‧Rough cut section

30‧‧‧Functional Structure Formation Department

40‧‧‧Transportation Department

50‧‧‧Precision cutting department

60‧‧‧Assembly Department

61‧‧‧ grasping hands

71‧‧‧Light source device

73‧‧‧ surface light source device

80‧‧‧Continuous resin sheet

81‧‧‧Light scattering point (functional part)

82‧‧‧ dot pattern (functional structure)

90‧‧‧Light guide plate (optical sheet)

90a‧‧‧A region that is precisely cut to the target size (product area)

95‧‧‧Rough cut single sheet (resin sheet)

95a‧‧‧ (rough cut single sheet 95) side

S1‧‧‧Resin sheet forming step

S2‧‧‧ rough cutting step

S3‧‧‧ Functional structure formation steps

S4‧‧‧Transfer steps

S5‧‧‧Precision cutting steps

S6‧‧‧ Assembly steps

P1‧‧‧1st place

P2‧‧‧2nd place

Fig. 1 is a schematic overall view of a manufacturing apparatus used in an embodiment.

Fig. 2 is a view showing a state of processing of a resin sheet in each step of the embodiment.

Figure 3 is a flow chart showing the steps of an embodiment.

4(a) and 4(b) are diagrams for explaining another embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following, the same or corresponding elements are designated by the same reference numerals, and the description thereof will not be repeated. Moreover, the dimensional ratio of the drawings is not necessarily consistent with those illustrated. In addition, in the description, the terms "upper" and "lower" are based on the convenience of the state shown in the drawing.

Fig. 1 is a schematic overall view of a manufacturing apparatus used in an embodiment. Fig. 2 is a view showing a state of processing of a resin sheet in each step of the embodiment. As shown in FIG. 1 , the apparatus 1 for manufacturing a surface light source device (hereinafter referred to as "surface light source device manufacturing apparatus 1") includes a resin sheet forming portion 10 provided at a first site P1, a rough cutting portion 20, and The functional structure forming unit 30; the precision cutting unit 50 and the assembly unit 60 installed in the second place P2; and the transport unit 40 installed between the first place P1 and the second place P2. First, an apparatus for manufacturing a light guide plate (optical sheet) will be described.

First, the resin sheet forming unit 10, the rough cutting unit 20, and the functional configuration forming unit 30 provided in the first place P1 will be described.

The resin sheet forming portion 10 is formed in a portion of the continuous resin sheet 80 which is a sheet-like resin which is continuous in one direction (feeding direction). For the resin sheet forming portion 10, an extrusion molding apparatus that forms a continuous resin sheet 80 by extrusion from a molten thermoplastic resin can be used. The extrusion molding apparatus includes: a resin inlet 11 for inputting a thermoplastic resin as a raw material; an extruder 12 for heating and melting the thermoplastic resin; and extruding the molten resin supplied from the extruder 12 into a sheet shape The die 13 and the first pressing roller 14, the second pressing roller 15, and the third pressing roller 16 for pressing the continuous resin sheet 80 extruded from the die 13 are formed.

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

The rough cut portion 20 is disposed between the resin sheet forming portion 10 and the functional structure forming portion 30. The rough cut portion 20 cuts the continuous resin sheet 80 continuously fed from the resin sheet forming portion 10 to obtain a portion of the rough cut single sheet 95 having a size larger than the target size of the optical sheet. The laser cutting device using laser light is included in the example of the rough cutting portion 20. As the laser light source of the laser cutting device, for example, a carbon dioxide gas laser, a YAG (Yttrium Aluminum Garnet) laser, an excimer laser, or the like is suitably used. Further, examples of the rough cutting portion 20 may be a cutting machine, a rotary knife, a shearing machine, or the like.

The functional structure forming portion 30 forms one or more functional structures on one surface 95a of the rough-cut single sheet 95 continuously fed from the resin sheet forming portion 10. The functional structure includes, for example, a dot pattern 82 in which light scattering dots (functional portions having a reflection function) 81 for diffusely reflecting light are arranged in a specific rule. The functional structure is formed by printing light scattering dots on one side 95a of the rough cut single sheet 95.

As the functional configuration forming portion 30, an ink jet device that prints the dot pattern 82 by ejecting droplet-shaped light-reflective ink from one surface 95a of the rough-cut single sheet 95 can be used. The ink jet apparatus can be formed, for example, in the form of droplets of ink which are ejected from a plurality of nozzles in the width direction of the rough cut single sheet 95 as a whole. It is preferable to print the specific dot pattern 82 by ejecting the ink while continuously moving the rough-cut single sheet 95 at a constant speed. Further, the ink may be ejected in a state where the rough cut single sheet 95 is stopped, and the rough cut single sheet 95 is moved to the next printing position, and then stopped (intermittent conveyance), and the specific dot pattern 82 is printed. As shown in FIG. 2, the functional structure forming portion 30 prints a specific dot pattern 82 on the region 90a of the target optical sheet.

As the ink ejected to the rough-cut single sheet 95, as long as it is an ink which forms a light scattering point by hardening or drying, it is used, for example, an ultraviolet curable ink, an aqueous ink or a solvent. Ink. Among these, from the viewpoints of ease of environmental measures and the like, ultraviolet curable inks and aqueous inks are preferred. In the case where an ultraviolet ray hardening ink is used, it is hardened by an ultraviolet lamp (ultraviolet lamp) or the like. In the case of using an aqueous ink or a solvent ink, the ink is dried by a drying device to form a light scattering point. When an inkjet device is used as the functional structure forming portion 30, a plasma processing portion that performs plasma processing may be provided on the upstream side of the functional structure forming portion 30.

Next, the transport unit 40 installed between the first place P1 and the second place P2 will be described. In other words, the conveying unit 40 is disposed between the functional configuration forming unit 30 and the precision cutting unit 50 . The conveyance unit 40 is a portion that conveys the rough cut single sheet 95 that forms the dot pattern 82 produced in the first place P1 to the second place P2. Between the first place P1 and the second place P2, the rough cut single sheet 95 can be conveyed by a person's hand, or the rough cut single sheet 95 can be conveyed by a transfer machine like a transfer robot.

Further, in the conveying unit 40, the rough-cut single sheet 95 can be conveyed by using an automobile, a railway, a ship, or an airplane. After the rough-cut single-sheet 95 is conveyed by the conveyance unit 40, the rough-cut single sheet 95 is precisely cut by the precision cutting unit 50, and the end portion thereof is removed to form an optical sheet of a target size. When transporting by the transport unit 40, it is not necessary to strictly perform the binding for protecting the end faces of the rough-cut single sheet 95.

Further, in the present invention, the cutting of the resin sheet by the precision cutting portion 50 is performed by irradiating the laser light or by using a punching device, so that it is not necessary to polish the end surface of the obtained optical sheet. As described in the column of the prior art, previously, the cutting of the continuous resin sheet was carried out without using a laser beam or a punching device, so that it is necessary to polish the end faces of the cut resin sheet. When the end face of the resin sheet is ground after the diffusion function or the reflection function is imparted, there is a possibility that the surface of the resin sheet which imparts a diffusion function or a reflection function is damaged or contaminated due to vibration or chips at this time, which is not preferable. Therefore, previously, the end faces of the resin sheets were ground before the diffusion function or the reflection function was imparted. In other words, the continuous resin sheet is cut so as to become the size of the target optical sheet, and the end surface is polished to impart a diffusion function or a reflection function. Create optical sheets. When the optical sheet is shipped out, it is necessary to strictly carry out the bale for protecting the end surface of the optical sheet so as not to be damaged, and the bale and the unfolding require labor. However, according to the present invention, it is only necessary to carry out the rough-cut single sheet 95, so that the bundle for protecting the end faces can be implemented less strictly.

In order to convey a large number of rough-cut single-sheet sheets 95, it is preferable to bundle a plurality of rough-cut single-sheet sheets 95 and the like, and then bundle them by the conveyance unit 40, and then bundle them.

Furthermore, the steps of the bale and unbundling are not shown in FIG.

Moreover, as already described, the bale may also be a bundle that is not strictly.

The precision cutting unit 50 precisely cuts the rough cut single sheet 95 which is formed by the conveyance unit 40 and forms the dot pattern 82, and forms a portion of the light guide plate 90 of the target size. The precision cutting unit 50 preferably uses a cutting device that does not require the final processing of the cut surface after cutting, in other words, performs mirror processing or zigzag processing simultaneously with cutting (see FIG. 4( a )). Broken device. The precision cutting unit 50 includes a laser cutting device that uses laser light. As the laser light source of the laser cutting device, for example, a carbon dioxide gas laser or a YAG laser, an excimer laser or the like is suitably used.

The size at which the rough-cut single-sheet 95 is precisely cut is selected in such a manner as to suit the target screen size of the surface light source device. The size is usually 120 mm in the short side direction and 220 mm in the long side direction; the short side direction is 1250 mm, and the long side direction is 2220 mm or less. Further, the length of the diagonal when the rough cut single sheet 95 is precisely cut is usually 25 cm or more and 250 cm or less.

The assembly unit 60 is a part in which at least the light guide plate 90, the light source device 71, and the components of the light guide plate 90 and the light source device 71 are connected to manufacture the surface light source device 73. An example of a component that connects the light guide plate 90 and the light source device 71 is a frame. In the assembly portion 60, the light guide plate 90 obtained by the precision cutting portion 50 is gripped by the gripping hand 61, and moved to a position where the frame is disposed. Further, the light source device 71 is grasped by the gripping hand 61 and moved to a position where the frame is disposed. Then, the light guide plate 90 is fixed to the light source device 71 via the frame, and is grouped as the surface light source device 73. Installed.

In the manufacturing apparatus 1 shown in FIG. 1, the continuous resin sheet 80 and the rough-cut single sheet 95 are transferred from the resin sheet forming portion 10 to the functional structure forming portion 30, and the rough cut single sheet 95 and The light guide plate 90 is transferred from the precision cutting unit 50 to the assembly unit 60 using a transfer device. Examples of the transport device include a transport roller, a table transport shuttle, a belt conveyor, a transport roller, and an air suspension transfer device.

Next, an example of a manufacturing procedure of the light guide plate 90 will be described. Figure 3 is a flow chart showing the steps of an embodiment. As shown in FIG. 3, the manufacturing process of the light guide plate of the present embodiment includes a resin sheet forming step S1, a rough cutting step S2, a functional structure forming step S3, a transport step S4, and a transfer step S4 performed in the first place P1. The precise cutting step S5 and the assembly step S6 performed by the second place P2. Hereinafter, each step will be described in order.

First, the steps performed in the first place P1 will be described. In the resin sheet forming step S1, the continuous resin sheet 80 is formed. In the example of the method of forming the continuous resin sheet 80, an extrusion molding method of extruding a molten thermoplastic resin to form a continuous resin sheet is included. In the extrusion molding method, for example, an acrylic resin is melt-kneaded as a thermoplastic resin and extruded, and is sandwiched and pressed by various pressing rolls. Thereby, a continuous resin sheet 80 having a specific thickness is formed. The thickness of the continuous resin sheet 80 is usually 0.1 mm or more and 2.0 mm or less, preferably 0.1 mm or more and 1.0 mm or less, more preferably 0.2 mm or more and 0.7 mm or less.

The rough cutting step S2 is performed between the resin sheet forming step S1 and the functional structure forming step S3. In the rough cutting step S2, the continuous resin sheet 80 fed from the resin sheet forming step S1 is cut, and a rough-cut single sheet 95 having a size larger than the target size of the optical sheet is obtained (see FIG. 2). In the example of the method of cutting the continuous resin sheet 80 to obtain the rough-cut single sheet 95, a method of cutting the continuous resin sheet 80 by laser light is included. Further, an example of a method of cutting the continuous resin sheet 80 to obtain the rough-cut single sheet 95 may be a method using a cutter, a rotary knife, a shearing machine, or the like.

In the functional structure forming step S3, the rough cut single piece sent from the coarse cutting step S2 One surface 95a of the sheet 95 forms one or more functional structures. The functional structure is, for example, a dot pattern 82 in which a light scattering point (functional portion) 81 having a reflection function is arranged in a specific rule. The functional structure is formed by printing a light scattering spot on one face 95a of the roughly cut single sheet 95. The dot pattern 82 which is arranged in a specific rule includes a dot pattern in which the shape of the light scattering spot S1 becomes larger as the distance from the end surface of the incident surface is increased, and a dot pattern in which the density of the light scattering dots 81 becomes higher. . In the example of the method of printing the dot pattern 82, the ink jet method of ejecting the droplet-shaped ink ejected from the nozzle onto the surface 95a of the rough-cut single sheet 95 is included.

In the transporting step S4, the rough-cut single-sheet 95 having the functional configuration is transported from the first location P1 to the second location P2 in which the precise cutting step S5 described below is performed. In the transporting step S4, a rough-cut single sheet 95 having a functional structure can be transported by using an automobile, a railway, a ship, or an airplane. After the transporting step S4, the rough cut single sheet 95 is precisely cut by the precision cutting step S5, and the end portions thereof are removed to obtain an optical sheet of a target size, so that it is not strictly required for protection in the transporting step S4. The bundle of the end faces of the rough cut single sheet 95.

In order to convey a large number of rough-cut single-sheet sheets 95, it is preferable to bundle a plurality of rough-cut single-sheet sheets 95 and the like, and to carry them in a transporting step S4, and then unpack them. However, the bale can also be a non-strict bale.

In the precision cutting step S5, the rough cut single sheet 95 conveyed to the printing dot pattern 82 of the precision cutting step S5 is precisely cut into a target size, thereby forming a light guide plate (optical sheet) 90. In the example of the method of precisely cutting the rough cut single sheet 95 into the target size, a method of cutting the rough cut single sheet 95 by laser light is included. Further, as a method of cutting the rough-cut single sheet 95, it is preferable to perform mirror processing at the same time as cutting; or as shown in Fig. 4(a), zigzag processing is performed at the same time as cutting. A method in which the surface is applied to the processing of the uneven shape in which the continuous resin sheet extends in the thickness direction.

In the assembly step S6, at least the light guide plate 90, the light source device 71, and the components connecting the light guide plate 90 and the light source device 71 are assembled to manufacture the surface light source device 73. An example of a component that connects the light guide plate 90 and the light source device 71 is a frame. Can also be carried out to install the surface light source A step of assembling a liquid crystal display device, an optical film, or the like to a frame to manufacture a transmissive image display device.

Next, the effects of the above-described light guide plate and method of manufacturing the surface light source device will be described. In the method of manufacturing the surface light source device, between the functional configuration forming step S3 and the precision cutting step S5, the rough-cut single sheet 95 on which the dot pattern 82 is formed is transferred from the first place P1 to the second place P2. Step S4 is therefore interrupted between the steps. In the precise cutting step S5 and the assembling step S6, the steps are continuously performed without interruption. When the method of manufacturing the surface light source device of the above-described embodiment and the method of manufacturing the surface light source device of the above-described embodiment are compared, the optical sheet obtained by precisely cutting the target size is transferred to the former, and the latter is conveyed precisely. The optical sheet in the state before the target size (here, the rough cut single sheet 95) is broken. In the method of manufacturing a surface light source device according to the above-described embodiment, even if the end surface of the optical sheet having a larger size than the target size (here, the rough cut single sheet 95) is damaged during transport, the damaged portion can be refined. The close step S5 is cut and removed. That is, a new end face is formed in the precision cutting step S5. The optical sheet on which the new end face is formed (here, the light guide plate 90) is directly assembled to the surface light source device 73. Therefore, the strictness of the end face of the optical sheet for protecting the end face of the optical sheet obtained by precisely cutting the target size in the manufacturing method of the above-described conventional surface light source device can be eliminated or alleviated. Bundling, and unpacking of assembly steps. As a result, productivity can be improved.

The embodiment of the present invention has been described above, but the present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the invention.

In the above embodiment, an extrusion molding method is used as a method of molding the continuous resin sheet 80, and an example in which the continuous resin sheet 80 is formed by using an extrusion molding apparatus is described as an example of the method. It is not limited to this. For example, a casting method in which a raw material is poured into a template and polymerized and formed can be used. Examples of the casting method include a continuous casting method using an endless belt including a continuous stainless steel plate or the like. in particular, The method includes the following steps: injecting the space formed by the opposing faces of one of the pair of rings and the two pads that follow the movement of the ring by a specific interval, and injecting The polymerizable raw material after melting of the initiator is polymerized and cured, and the formed plate-shaped polymer is peeled off from the endless belt and taken out.

In the above embodiment, the ink jet method is used as a method of printing the dot pattern 82 on one surface 95e of the rough-cut single sheet 95, and a dot pattern is printed on one surface 95a of the rough-cut single sheet 95 using an ink jet apparatus. The example of 82 has been described as an example of the method, but the present invention is not limited thereto.

For example, in the example of the method of printing the dot pattern 82, a screen printing method is included. Further, in the functional structure forming step S3, a method of forming a functional structure in which a functional portion having a reflecting function or a diffusing function is arranged with a specific rule includes a method of irradiating laser light to form a functional structure including a plurality of concave portions. And a method of forming a functional structure including a plurality of concave portions or convex portions by pressing a stamper having fine concavities and convexities.

In the above embodiment, a method of cutting the rough cut single sheet 95 using the laser light cutting method as the printing dot pattern 82, and a method of cutting the rough cut single sheet 95 using a laser cutting device will be described. An example has been described as an example of the method, but the present invention is not limited thereto. For example, the light guide plate (optical sheet) 90 may be formed by punching the rough-cut single sheet 95 printed with the dot pattern 82 into the shape of the light guide plate 90. An example of punching a rough cut single sheet 95 into a desired shape includes a punching device including a THOMSON knife or the like.

In the above-described embodiment, in the resin sheet forming step S1, the surface of the light guide plate 90 on the side which is the light emitting surface is not provided with a shape such as unevenness, that is, the first to third portions of the extrusion molding apparatus. Although an example in which no irregularities are formed on any of the pressing surfaces of the pressing rolls 14, 15, and 16 has been described, the present invention is not limited thereto. For example, in the resin sheet forming step S1, a ridge portion or the like which extends in one direction may be formed on the surface of the continuous resin sheet 80 which is the side on which the light exit surface is formed. In this case, it can be applied to the second pressing roller 14 of the extrusion molding apparatus. A convex portion or the like is formed by providing irregularities or the like on the circumferential surface. Further, similarly, an embossed surface having a diffusion function can be formed.

Further, in the above-described embodiment, in the functional configuration forming step S3, an example in which one region 90a is formed in the width direction of the rough-cut single sheet 95 and the dot pattern 82 is printed in the region 90a is described. However, the invention is not limited thereto. For example, two regions 90a (see FIG. 4(b)) or three or more regions 90a may be formed in the width direction of the rough-cut single sheet 95. One dot pattern 82 is printed and formed for each of the regions 90a. Then, for each dot pattern 82, one light guide plate (optical sheet) 90 is obtained.

In the transporting step S4 of the above-described embodiment, the rough cut sheet may be conveyed while the protective film is bonded to at least one of the surface to be printed and the surface opposite to the surface to be printed (non-printing surface). Sheet 95. That is, before the transfer step S4, a bonding step of bonding a protective film may be included. Thereby, damage to the printed surface and the non-printed surface at the time of conveyance can be prevented. Further, in this case, the step of applying the antistatic liquid may be included after the bonding step of bonding the protective film.

Further, in the above embodiment, an example of manufacturing a light guide plate for a backlight of a so-called edge light type, that is, a light scattering point 81 having a reflection function is printed on one surface 95a of the rough cut single sheet 95. The example of the dot pattern 82 has been described, but the present invention is not limited thereto. For example, in the present invention, a light diffusing plate (optical sheet) for a so-called direct type backlight can be formed. In this case, in the functional configuration forming step S3, a dot pattern including a diffusion point (functional portion having a diffusion function) is formed on one surface 95a of the rough-cut single sheet 95 using ink having light diffusibility or the like. In the case of manufacturing such a light diffusing plate, productivity can also be improved. Further, the light-diffusing sheet thus produced may be disposed such that the surface on which the pattern is printed is the light-emitting surface, or the surface on which the pattern is printed may be placed on the light-incident surface. However, it is preferable to arrange such that the surface on which the pattern is printed is the light exit surface.

[Industrial availability]

According to the method for producing an optical sheet of the present invention and the method for producing a surface light source device, productivity can be improved.

71‧‧‧Light source device

73‧‧‧ surface light source device

80‧‧‧Continuous resin sheet

81‧‧‧Light scattering point (functional part)

82‧‧‧ dot pattern (functional structure)

90‧‧‧Light guide plate (optical sheet)

90a‧‧‧A region that is precisely cut to the target size (product area)

95‧‧‧Rough cut single sheet (resin sheet)

S1‧‧‧Resin sheet forming step

S2‧‧‧ rough cutting step

S3‧‧‧ Functional structure formation steps

S4‧‧‧Transfer steps

S5‧‧‧Precision cutting steps

S6‧‧‧ Assembly steps

Claims (6)

A method for producing an optical sheet, comprising: a functional structure forming step of forming at least one side of a resin sheet to form one or more functional structures having a reflecting function or a diffusing function; and a precise cutting step One or more optical sheets of a target size are obtained by irradiating laser light or by cutting a resin sheet having one or more of the above functional structures by using a punching device. The method of manufacturing an optical sheet according to claim 1, wherein the functional structure forming step and the transferring step further comprise a bonding step of forming a surface of the functional structure and forming the functional structure. The protective film is attached to at least one of the faces on the opposite side. The method of producing an optical sheet according to claim 1 or 2, wherein in the fine cutting step, the resin sheet having one or more of the functional structures formed thereon is cut to obtain one or more optical sheets of a target size. At the same time, the end surface of the optical sheet is provided with a concavo-convex shape. The method for producing an optical sheet according to claim 1 or 2, further comprising: a resin sheet forming step of forming the resin into a continuous resin sheet in a continuous direction in a sheet direction; and a rough cutting step, And cutting the continuous resin sheet continuously fed from the resin sheet forming step to obtain a rough-cut single sheet having a size larger than the target size; and the resin sheet is obtained by the coarse cutting step The above rough cut single sheet. The method of manufacturing the optical sheet of claim 1 or 2, wherein between the functional structure forming step and the transferring step, the method further comprises: The packing step of packaging the resin sheet; the carrying step of transporting the packaged resin sheet; and the unpacking step of unpacking the resin sheet that has been bundled and transported. A method of manufacturing a surface light source device, comprising: a step of manufacturing an optical sheet by the method for producing an optical sheet according to any one of claims 1 to 5; and assembling the optical sheet and the light source device to manufacture a surface light source The steps of the device.