TW201439580A - Optical sheet fabrication method - Google Patents

Abstract

By an optical sheet fabrication method according to one embodiment of the present invention, fabricated is an optical sheet (90) having a main surface (90A) to which given functions have been added. The fabrication method is provided with a step (S2) in which a light-transmitting sheet (21) is affixed to a support plate (40), and a step (S3) in which a process to add at least one of the given functions is carried out in a non-contact manner on a surface (21a) of the light-transmitting sheet, which is to be the main surface, while the support plate to which the light-transmitting sheet has been attached is conveyed in a given direction.

Description

Optical sheet manufacturing method

The present invention relates to a method of producing an optical sheet.

As an example of the optical sheet, for example, a light guide plate or a light diffusing plate used in a transmissive image display device such as a liquid crystal display device is used. Such an optical sheet such as a light guide plate and a light diffusing plate has a light-transmitting sheet, and has a specific function to the surface of the light-transmitting sheet. The above surface of the light transmissive sheet is also the main surface of the optical sheet. Examples of specific functions include liquid repellency and light scattering properties. The liquid repellency can be imparted, for example, by plasma treatment of the surface. The light-scattering property can be specified by an inkjet printing method on the surface of a light-transmitting sheet which is an optical sheet as a light guide plate as disclosed in Japanese Laid-Open Patent Publication No. Hei 9-68614 (Patent Document 1). The printed pattern is formed by forming a plurality of printed dots. In the ink jet printing method exemplified, the ink jet nozzle is disposed away from the surface. Similarly, in the plasma treatment, since the plasma generated between the surface and the electrode is utilized, the surface is away from the electrode. Therefore, the above-described inkjet printing method and plasma processing can be exemplified by a non-contact function imparting a specific function to the surface.

In recent years, a transmissive image display device such as a liquid crystal display device has been expected to be thinner. For example, in a transmissive image display device mounted on a very thin notebook computer such as an Ultrabook, the optical sheet used in the transmissive image display device must also be thinner.

If the thickness of the optical sheet is thin, the optical sheet has a thickness of the light transmissive sheet Also thin. In this case, in the process of manufacturing the optical sheet, the thin translucent sheet which becomes an optical sheet is easily warped or is easily deflected. Therefore, when a non-contact function imparting treatment technique is used to impart a function to the surface of a thin translucent sheet, there is a case where it is not possible to stably impart a desired function to the surface of the main surface of the optical sheet.

Accordingly, it is an object of the present invention to provide a method for producing a thin optical sheet in which a main surface is more stably imparted with a specific function.

One aspect of the present invention is a method of making an optical sheet having a specific function imparted to a main surface. The method includes the steps of: fixing the light-transmitting sheet to the support sheet; and conveying the support sheet to which the light-transmitting sheet is fixed in a specific direction on one side, and facing the light-transmissive sheet which becomes the main surface The surface performs a function imparting process imparting at least one function in a non-contact manner.

In this method, when the function imparting treatment is performed on the light-transmitting sheet in a non-contact manner, the light-transmitting sheet is fixed to the support sheet. Since the light-transmitting sheet is fixed to the support sheet, warpage or deflection does not occur even if the light-transmissive sheet subjected to the treatment is thinned. Therefore, even if the support sheet to which the light-transmitting sheet is fixed is conveyed, the surface of the light-transmitting sheet which is the main surface of the optical sheet is subjected to the function imparting treatment, and the surface can be surely given a specific function. Therefore, according to the above method, it is possible to manufacture a thin optical sheet in which the main surface is more stably imparted with a specific function.

In one embodiment, the thickness of the light-transmitting sheet may be 1.5 mm or less.

In one embodiment, the function providing treatment may be a printing process in which a specific printing pattern is formed by a printing method on the surface, a light-scattering printing process is applied to the surface, a liquid-repellent treatment is applied to the surface, or a surface is applied. A hydrophilic hydrophilization treatment is imparted.

In one embodiment, the step of performing at least one function imparting treatment in a non-contact manner may further include the steps of: performing a plasma treatment as a liquid-repellent treatment for imparting liquid repellency to the surface; and performing a printing process, the printing process Forming a specific printed pattern by the inkjet printing method on the surface on which the liquid-repellent treatment has been performed to impart dispersion to the surface Shootability.

In this case, since the light-transmitting sheet is fixed to the support sheet, warpage or deflection does not occur on the light-transmitting sheet even if the light-transmissive sheet is thinned. When the surface of the sheet is subjected to plasma treatment, the liquid repellency can be uniformly imparted to the surface. Further, in a state where warpage or deflection does not occur in the light-transmitting sheet, a specific printing pattern is imparted to the surface thus uniformly imparted with liquid repellency by an inkjet printing method, so that it can be formed on the surface. Close to the specific print pattern of the design.

In one embodiment, the functional imparting treatment system is treated as a plasma treatment that imparts a liquid-repellent liquid treatment to the surface, and the surface is opposed to an electrode that faces the surface and is used to generate plasma in the plasma treatment. The distance may be 1.0 mm or more and 5.0 mm or less.

In one embodiment, the function-imparting processing system forms a specific printing pattern on the surface by an inkjet printing method, a printing process for imparting light-scattering property to the surface, and an inkjet nozzle that ejects ink in an inkjet printing method. The distance from the surface may be 0.4 mm or more and 3.5 mm or less.

In one embodiment, the support plate may have a positioning portion for fixing the light-transmitting sheet to a specific position on the support plate.

The position of the light-transmitting sheet relative to the support plate is defined by the positioning portion. Therefore, the function of imparting light can more appropriately impart a function to the light-transmitting sheet.

In one embodiment, the size of the arrangement area in which the light-transmitting sheet is disposed in the support plate may be smaller than the size of the light-transmitting sheet.

In this case, one of the light-transmitting sheets protrudes outward from the support plate. Therefore, when the light-transmitting sheet or the optical sheet as a product is to be detached from the support sheet, it is easy to remove.

In one embodiment, the amount of warpage of the support plate may be set to 0.1 mm or less. The amount of warpage mentioned herein refers to the maximum value of the distance from the horizontal plane to the bottom of the support plate when the support plate having a length of 1 m and a width of 1 m is placed on a horizontal plane. Further, an example of the thickness of the support plate is 2.0 mm.

According to the present invention, it is possible to provide a method of manufacturing a thin optical sheet in which a main surface is more stably imparted with a specific function.

10‧‧‧Resin sheet forming department

11‧‧‧Resin input

12‧‧‧Extrusion machine

13‧‧‧ mould mouth

14‧‧‧1st squeeze roller

15‧‧‧2nd squeeze roller

16‧‧‧3rd squeeze roller

20‧‧‧Continuous resin sheet

21‧‧‧Thin resin sheet

21a‧‧‧Surface

30‧‧‧cutting department

40‧‧‧Support board

40a‧‧‧Edge

40b‧‧‧Edge

40c‧‧‧Configuration area

41‧‧‧ Positioning Department

41-1‧‧‧ Positioning rod (positioning part)

41-2‧‧‧ Pin (positioning department)

42‧‧‧through holes

50‧‧‧Transporting device

50-1‧‧‧Transport roller

50-2‧‧‧belt conveyor

50-2a‧‧‧Conveyor belt

50-2b‧‧‧through hole

60‧‧‧ Plasma processing unit

61A‧‧‧electrode

61B‧‧‧electrode

62‧‧‧Power source

70‧‧‧Printing and Processing Department

71‧‧‧Inkjet nozzle

72‧‧‧ Hardening Department

80‧‧‧Light scattering points

90‧‧‧ Optical sheet

90a‧‧‧ main face

90b‧‧‧Light exit surface

100‧‧‧Transmissive image display device

110a‧‧ Point light source

110A‧‧‧Light source department

110B‧‧‧Light source department

120‧‧‧Transmission type image display unit

130‧‧‧ surface light source device

140‧‧‧Attraction device

11‧‧‧ distance

12‧‧‧ Distance

T1‧‧‧Sheet thickness

T2‧‧‧ plate thickness

T3‧‧‧ thickness of the positioning rod

Fig. 1 is a flow chart showing a method of manufacturing an optical sheet according to an embodiment.

Fig. 2 is a view for explaining an example of the preparation steps shown in Fig. 1.

Figure 3 is a diagram showing the fixing step shown in Figure 1.

4 is a view showing a relationship between an arrangement region and a size of a resin sheet as an example of a light-transmitting sheet.

Fig. 5 is a view showing the steps of the liquid dispensing process shown in Fig. 1.

Fig. 6 is a view showing an arrangement relationship between an electrode for generating plasma and a resin sheet as an example of a light-transmitting sheet.

Fig. 7 is a view showing the printing process steps shown in Fig. 1.

Figure 8 is a plan view of an optical sheet.

FIG. 9 is a view showing a schematic configuration of a transmissive image display device to which an optical sheet as a light guide plate manufactured by the manufacturing method shown in FIG. 1 is applied.

Fig. 10 is a view showing another example of the positioning unit.

FIG. 11 is a view showing an example of a method of sucking a resin sheet as an example of a light-transmitting sheet onto a support sheet side and fixing the resin sheet to a support sheet.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same elements are denoted by the same reference numerals, and the description thereof will be omitted. The size ratio of the drawings is not necessarily consistent with the description. The words "upper" and "lower" in the description are simple words based on the state shown in the drawing.

Fig. 1 is a flow chart showing a method of manufacturing an optical sheet according to an embodiment. An example of an optical sheet manufactured by the manufacturing method shown in FIG. 1 is applied to a transmission pattern such as a liquid crystal display device. A light guide plate like a display device. In the following description, the optical sheet as a product produced by the production method shown in Fig. 1 is a light guide plate unless otherwise specified.

As shown in FIG. 1, a method of manufacturing an optical sheet includes a step of preparing a thin resin sheet (hereinafter referred to as "preparation step") S1, and a step of fixing a thin resin sheet to a support sheet (hereinafter, referred to as " The fixing step ") S2; and a step of giving a specific function to the main surface of the thin resin sheet (hereinafter referred to as "function imparting step") S3. Each step will be described.

(1) Preparation steps

The preparation step S1 includes a step of producing a continuous resin sheet which is a continuous resin sheet in one direction (hereinafter referred to as a "continuous resin sheet manufacturing step") S1A; and cutting the continuous resin sheet into a specific one. The step of size (hereinafter referred to as "cutting step") S1B. In one embodiment, the steps S1A, S1B are carried out, for example, by the manufacturing apparatus shown in FIG. 2. Fig. 2 is a diagram for explaining an example of a preparation step. The manufacturing apparatus shown in Fig. 2 utilizes an apparatus having an extrusion molding method.

The continuous resin sheet manufacturing step S1A and the cutting step S1B will be described with reference to Figs. 1 and 2 .

(Continuous resin sheet manufacturing step)

In the continuous resin sheet manufacturing step S1A, a thermoplastic resin as a raw material is introduced into the extruder 12 via the resin inlet 11 of the extrusion molding apparatus included in the resin sheet forming section 10 shown in FIG. 2 . The resin sheet forming portion 10 is a part of a manufacturing apparatus.

Examples of the thermoplastic resin introduced from the resin inlet port 11 include an acrylic resin, a styrene resin, a methyl methacrylate (PMMA) resin, a polystyrene (PS) resin, and MS (methyl acrylate-styrene). Copolymer) resin, polycarbonate resin, AS (acrylonitrile-styrene copolymer) resin, cycloolefin resin, polyethylene resin, polypropylene resin, and polyethylene terephthalate resin. Further, an additive such as a light diffusing agent, an ultraviolet absorber, a heat stabilizer, or a photopolymerization stabilizer may be added to the resin exemplified.

The thermoplastic resin that has been introduced into the extruder 12 is heated and melted in the extruder 12. The heat-melted thermoplastic resin is continuously extruded from the die 13 into a sheet-like resin sheet, whereby a continuous resin sheet 20 as a light-transmitting sheet is formed.

The continuous resin sheet 20 continuously extruded from the die 13 is pressed by the first squeeze roll 14, the second squeeze roll 15, and the third squeeze roll 16 located in the subsequent stage of the extrusion molding apparatus. Examples of the first pressing roller 14, the second pressing roller 15, and the third pressing roller 16 are metal rollers. The first squeeze roller 14, the second squeeze roller 15, and the third squeeze roller 16 are disposed such that their rotation axes are substantially parallel to each other.

The continuous resin sheet 20 extruded from the die 13 is conveyed by the rotation of the first squeeze roll 14 and the second squeeze roll 15, and is then rotated by the rotation of the second squeeze roll 15. The continuous resin sheet 20 conveyed by the rotation of the second pressing roll 15 is further pressed by the second pressing roll 15 and the third pressing roll 16, thereby obtaining a thin continuous resin sheet 20.

The sheet thickness t1 of the continuous resin sheet 20 can be changed by the distance between the first pressing roller 14 and the second pressing roller 15, and the distance between the second pressing roller 15 and the third pressing roller 16. Adjust at least one of them. The sheet thickness t1 of the continuous resin sheet 20 which has been sent through the third pressing roll 16 or the resin sheet forming unit 10 is 0.1 mm or more and 1.5 mm or less, more preferably 0.2 mm or more and 1.0 mm or less. Further, it is preferably 0.3 mm or more and 0.5 mm or less.

(cutting step)

In the cutting step S1B, the continuous resin sheet 20 is cut into a specific size by the cutting portion 30 to form a resin sheet 21 having a specific size. The thickness of the continuous resin sheet 20 that has passed through the third pressing roll 16 is thin as exemplified, so that the resin sheet 21 of a specific size is referred to as a thin resin sheet 21. The specific size is the size of the optical sheet of the product, and is a size corresponding to the screen size of the transmissive image display device such as a device to which an optical sheet is applied, such as a liquid crystal display device.

The cutting unit 30 is located in the conveying direction of the continuous resin sheet 20 continuously fed from the third pressing roll 16 and is located in the subsequent stage of the third pressing roll 16, and constitutes one of the manufacturing apparatuses shown in FIG. section. The cutting portion 30 cuts the continuous resin sheet 20 in the width direction (the direction orthogonal to the conveying direction), for example. The cutting portion 30 can also cut the continuous resin sheet 20 in accordance with the size of the thin resin sheet 21, for example, in the conveying direction of the continuous resin sheet 20.

The cutting device used in the cutting unit 30 may be any device that can cut a resin sheet of a specific size from the continuous resin sheet 20. For example, the cutting unit 30 includes a laser cutting device that uses laser light and a punching device that punches the continuous resin sheet 20 into a desired shape. As the laser light source of the laser cutting device, for example, a carbon dioxide gas laser or a YAG (Yttrium Aluminum Garnet) laser or a excimer laser is suitably used. The reason for this is that it is easy to reduce the polishing treatment of the cut surface after cutting by using the laser light. An example of the polishing treatment of the cut surface after the cutting is the mirror surface processing of the cut surface. The punching device may be a device having a Thomson blade or the like as a punching die for punching the continuous resin sheet 20 into a desired shape.

In one embodiment, the cutting step S1B may further include: a rough cutting step of cutting a thin resin sheet having a size larger than a specific size from the continuous resin sheet 20; and a precision cutting step, which is self specific The thin resin sheet having a large size is further cut into a thin resin sheet 21 of a specific size.

In the embodiment in which the continuous resin sheet 20 is cut in two stages, the cutting device used in the rough cutting step may be a laser device as described above, or may be a cutting machine, a rotary knife, or a shearing machine. . The cutting device used in the precision cutting step is preferably a laser device as described above.

In the preparation step S1, the method of producing the continuous resin sheet 20 is exemplified by the method of extrusion molding, but it is not particularly limited as long as the continuous resin sheet 20 having a desired thickness can be produced.

For example, a casting method in which a raw material is poured into a template to be polymerized and formed, or the like can be used.

(2) fixed steps

In the fixing step S2, the prepared thin resin sheet 21 is fixed as a backing plate Support board 40. Figure 3 is a diagram showing the fixing step.

The support plate 40 is a rectangular or square plate in a plan view shape (a shape observed from the plate thickness direction). Examples of the material of the support plate 40 include glass, resin, and metal. An example of the plate thickness t2 of the support plate 40 is 2.0 mm. If the rigidity and flatness of the support plate are expressed by the amount of warpage, it can be set to 0.1 mm or less. The amount of warpage mentioned here refers to the maximum height in the vertical direction based on the horizontal plane when the support plate 40 having a length of 1 m is placed on a horizontal plane.

The thin resin sheet 21 can be fixed to the support sheet 40 by, for example, an adhesive tape, or can be simply fixed to the support sheet 40 by an adhesive. When the thin resin sheet 21 is simply fixed to the support sheet 40 by the adhesive, the thin resin sheet 21 may be fixed to the support sheet 40 to such an extent that the thin resin sheet 21 is peeled off from the support sheet 40.

In one embodiment, the support plate 40 may have a positioning portion 41 for fixing the thin resin sheet 21 to a specific position on the support plate 40.

As shown in FIG. 3, the positioning portion 41 may be, for example, an L-shaped positioning rod 41-1 formed along two orthogonal edge portions 40a and 40b of the support plate 40. In the case where the support plate 40 has the convex portion 41-1, the thickness t3 of the positioning rod 41-1 is 1.0 mm. The positioning portion 41 may be a position that defines the position of the thin resin sheet 21, and may be, for example, a rectangular rod as shown in FIG. 3 or a plate shape. Further, as described below, it may be a pin.

In the support plate 40, the size of the region (hereinafter referred to as the arrangement region) 40c in which the thin resin sheet 21 is disposed is as shown in FIG. 4, and may be smaller than the thin resin sheet 21. Fig. 4 is a view showing the relationship between the arrangement area and the size of the thin resin sheet. The support plate 40 shown in Fig. 4 has a positioning rod 41-1. The arrangement region 40c is a region in contact with the thin resin sheet 21 on the surface of the support sheet 40 on the side where the thin resin sheet 21 is disposed. When the arrangement region 40c is smaller than the thin resin sheet 21, the side surface of the thin resin sheet 21 protrudes outward from the support plate 40, so that it is easy to operate the support sheet 40 with the thin resin sheet attached thereto. Moreover, for the same reason, in the subsequent step, the thin resin sheet 21 or the optical sheet as a product is easily detached from the support sheet 40. Since the side of the thin resin sheet 21 is more convex than the support plate 40 Therefore, when processing is performed on the side surface of the thin resin sheet 21, the processing is easy. In FIG. 4, the two side surfaces of the four side surfaces of the thin resin sheet 21 which are not in contact with the positioning rod 41-1 protrude from the support plate 40.

(3) Function assignment step

In the function providing step S3, the support sheet 40 to which the thin resin sheet 21 is fixed is conveyed in one direction (specific direction), and the surface 21a which is one main surface of the thin resin sheet 21 is given a specific surface. At least one treatment of the function. As shown in FIG. 1, an example of this step includes a liquid dispensing process step S3A and a printing process step S3B. The surface 21a of the thin resin sheet 21 is also the main surface of the optical sheet to be produced.

(liquid dispensing step)

In the liquid-repellent treatment step S3A, as shown in FIG. 5, the support plate 40 to which the thin resin sheet 21 is fixed is placed on the transport device 50 and transported in one direction (the direction indicated by the arrow in FIG. 5). The liquid-repellent treatment for imparting liquid repellency to the surface 21a is performed. In FIG. 5, as an example of the conveyance device 50, a plurality of conveyance rollers 50-1 are displayed. In addition to the conveyance roller 50-1, the conveyance device 50 includes a shuttle table, a belt conveyor, a conveyance roller, an air suspension transfer device, and the like. Figure 5 is a diagram showing the steps of the liquid dispensing process.

The example of liquid dispensing treatment utilizes the non-contact treatment of various energy lines. The treatment using various energy lines utilizes energy lines to impart a liquid-repellent treatment to the surface 21a. In the case of the energy line, it includes a plasma, an electron beam, an ion beam, and the like. In the case of the liquid-repellent treatment in the case of using the plasma treatment, the operation includes: after roughening the surface 21a by plasma etching, forming a liquid-repellent monomolecular film on the roughened surface; The surface 21a is fluorinated by a fluorine-based gas plasma; a film composed of a liquid-repellent compound is formed on the surface 21a by plasma CVD (Chemical Vapor Deposition); and the surface 21a is formed by plasma polymerization. A liquid-repellent film or the like is formed thereon.

In Fig. 5, as an example of the liquid-repellent treatment, the plasma is applied to the surface 21a. The form of processing. Fig. 6 is a view showing the arrangement relationship between the electrode for plasma generation and the thin resin sheet. In the form in which the plasma treatment is performed as the liquid-repellent treatment, the material of the support plate 40 is a material other than the metal.

As shown in FIG. 5, the support plate 40 to which the thin resin sheet 21 is fixed is conveyed to the plasma processing apparatus 60 by the conveyance apparatus 50. The support plate 40 with the thin resin sheet attached is transferred between the counter electrodes 61A and 61B provided in the plasma processing apparatus 60. At this time, electric power for generating plasma is supplied between the pair of electrodes 61A and 61B by the power source 62 such as an AC voltage source, whereby the surface 21a of the thin resin sheet 21 and the electrode 61A facing the surface 21a are used. The generated plasma is subjected to liquid dispensing treatment on the surface 21a. The plasma treatment system shown in Fig. 5 is mainly based on the fact that the surface 21a is fluorinated by using a fluorine-based gas plasma, but it may be treated by the above-mentioned other plasma.

While the support plate 40 is conveyed by the transfer device 50 to face the surface 21a of the thin resin sheet 21 for plasma treatment, the surface 21a of the thin resin sheet 21 is sequentially subjected to plasma treatment in a certain direction. Therefore, the above plasma treatment can be said to have a directional process.

Further, the electrode 61A is moved away from the surface 21a so that a fixed space is formed between the electrode facing the surface 21a and the surface 21a as shown in FIG. Therefore, the plasma treatment is a process for producing a non-contact between the electrode 61A of the plasma and the surface 21a. An example of the distance 11 between the surface 21a and the electrode 61A is 1.0 mm or more and 5.0 mm or less, preferably 1.0 mm or more and 3.0 mm or less.

(printing processing steps)

The printing process step S3B is performed after the liquid dispensing process step S3A. The printing process step S3B is a step of imparting light scattering properties to the liquid-repellent surface 21a by a printing method. This will be specifically described using FIG. 7. Figure 7 is a diagram showing the steps of the printing process.

In Fig. 7, a form in which an inkjet printing method is used is schematically shown as an example of printing processing.

As shown in FIG. 7, in the printing process step S3B, the thin resin sheet 21 is fixed. The support plate 40 is transported by the transport device 50 in one direction (the direction of the arrow shown in FIG. 7). The example of the conveying device 50 is the conveying roller 50-1 similar to the case of the liquid dispensing process, but may be another example shown in the description of the liquid dispensing process step S3A. The printing process step S3B may be performed downstream of the transport device 50 used in the liquid-repellent treatment step S3A in the place where the liquid-repellent treatment step S3A is performed, or may be carried out by a place different from the place where the liquid-repellent treatment step S3A is performed. Device 50 is implemented.

The inkjet nozzle 71 included in the printing processing unit 70 drops the droplet-shaped ink onto the surface 21a of the thin resin sheet 21 to be conveyed in a specific printing pattern. The dropped ink is hardened by the hardened portion 72, whereby a light scattering spot 80 as a printing dot is formed on the surface 21a. The hardened portion 72 is not particularly limited as long as the ink can be cured. For example, when the ink is an ultraviolet curable ink, the hardened portion 72 is an ultraviolet ray irradiated portion that irradiates ultraviolet rays, and may be a drying device when the ink is cured by drying. FIG. 7 shows a case where the ultraviolet ray irradiation unit (UV lamp) of the hardened portion 72 is used. Further, the hardened portion 72 is described as a part of the print processing unit 70, but may be a component different from the print processing unit 70. In other words, the printing processing unit 70 only needs to be able to print the ink onto the surface 21a in a specific printing pattern.

After the printing by the printing processing unit 70, the anti-static treatment for antistatic can be performed on the printing surface of the thin resin sheet 21. Examples of the antistatic treatment include a method using a corona treatment, a method of applying a solution containing a hydrophilic surfactant, and a method of applying a solution containing an antistatic agent.

The size of the light scattering spot 80 can be controlled by adjusting the amount of ink dripping. The particular printed pattern is typically a two-dimensional pattern. The two-dimensional pattern of the light scattering dots 80 can be formed by arranging a plurality of inkjet nozzles 71 in a direction orthogonal to the conveying direction of the support plate 40. Preferably, the specific printing pattern is printed by ejecting the ink while continuously moving the support sheet 40 at a constant speed. Further, a specific printing pattern may be printed by repeating the following operations (intermittent conveyance), and the above operation means that the continuous resin sheet 20 is stopped. In the stopped state, the ink is ejected, and the continuous resin sheet 20 is stopped until it is moved to the next printing position.

As shown in FIG. 7, in the case where a specific printing pattern is formed by the inkjet printing method, there is a fixed interval between the surface 21a and the inkjet nozzle 71 as shown in FIG. Therefore, the printing process by the inkjet printing method is a non-contact process. An example of the distance 12 between the surface 21a and the inkjet nozzle 71 is 0.4 mm or more and 3.5 mm or less, preferably 0.4 mm or more and 2.0 mm or less, and more preferably 0.4 mm or more and 1.0 mm or less. Further, in the above inkjet printing method, printing is sequentially performed in a certain direction. Therefore, the printing process using the above-described inkjet printing method can be said to have a directional process.

As described above, as shown in FIG. 1, the steps are performed in the order of the preparation step S1, the fixing step S2, the liquid-repellent processing step S3A, and the printing processing step S3B, whereby a thin resin sheet is obtained as shown in FIG. 21 and an optical sheet 90 having light scattering dots 80 formed on a surface 21a of the thin resin sheet 21 in a specific printing pattern. The surface 21a of the thin resin sheet 21 is the main surface 90a of the optical sheet 90. Figure 8 is a plan view of an optical sheet. As described above, such an optical sheet 90 can be applied to a transmissive image display device such as a liquid crystal display device as a light guide plate. The thickness t1 of the thin resin sheet 21 of the optical sheet 90 is, for example, 1.5 mm or less as described above. An arrangement pattern of the light scattering dots 80 shown in Fig. 8 is an example. In the case where the optical sheet 90 is used as a light guide plate, the light scattering dots 80 are formed by an arrangement pattern (or a printing pattern) corresponding to the characteristics of the light emitted from the light exit surface.

FIG. 9 is a view showing a schematic configuration of a transmissive image display device to which an optical sheet as a light guide plate manufactured by the manufacturing method shown in FIG. 1 is applied. In FIG. 9, the cross-sectional configuration of the transmissive image display device 100 is shown.

The transmissive image display device 100 includes an optical sheet 90, light source portions 110A and 110B disposed on the side of the optical sheet 90, and a transmissive type disposed on the front side (upper side in FIG. 9) of the optical sheet 90. Image display unit 120. The optical sheet 90 is usually located on the back side of the transmissive image display device 100 at the light scattering point 80, that is, when viewed from the optical sheet 90, and the transmissive type. The image display unit 120 is disposed on the opposite side. At least one optical film can be disposed between the optical sheet 90 and the transmissive image display unit 120. Examples of the optical film include a diffusion film, a ruthenium film, and a brightness enhancement film.

The light source portions 110A and 110B are disposed opposite to the side faces of the optical sheets 90 facing each other, in other words, the side faces of the thin resin sheets 21 facing each other. Each of the light source sections 110A and 110B has a plurality of point light sources 110a arranged in a line shape. An example of the point light source 110a is a light emitting diode. The light source units 110A and 110B are not limited to a plurality of point light sources, and may be linear light sources such as fluorescent lamps (cold cathode ray lamps). The light source sections 110A and 110B may include a reflector that reflects light on the side opposite to the optical sheet 90 as the light guide plate, so that light is efficiently incident on the optical sheet 90 side. In the example in which the light source portions 110A and 110B are disposed on the opposite sides of the optical sheet 90, the light source portions may be disposed on at least one side surface of the optical sheet 90. Therefore, for example, the light source unit may be disposed on each of the four side faces of the optical sheet 90.

The optical sheet 90 and the light source units 110A and 110B as the light guide plate shown in FIG. 9 constitute a surface light source device 130 that supplies planar light to the transmissive image display unit 120. When an optical film is provided between the transmissive image display unit 120 and the optical sheet 90, the optical film can also be regarded as a constituent element of the surface light source device 130.

The transmissive image display unit 120 illuminates the surface light emitted from the optical sheet 90 to display an image. The example of the transmissive image display unit 120 is a liquid crystal display panel in which a polarizing plate bonding body of a polarizing plate is disposed on both surfaces of a liquid crystal cell.

In the transmissive image display device 100 having the above configuration, the light output from the light source units 110A and 110B enters the optical sheet 90 from the side surface of the optical sheet 90 that faces the light source units 110A and 110B, respectively. The light incident into the optical sheet 90 is transmitted while being totally reflected on the optical sheet 90. During the transfer, one of the light incident into the optical sheet 90 is partially scattered at the light scattering point 80, whereby the surface 21b opposite to the surface 21a of the thin resin sheet 21 is emitted. In this case, the surface 21b of the thin resin sheet 21 serves as the light of the optical sheet 90. The exit surface 90b functions.

As described above, since light is emitted from the optical sheet 90 and a part thereof is emitted from the light exit surface 90b, the planar light is emitted from the light exit surface 90b. Since the planar light illuminates the transmissive image display unit 120 such as a liquid crystal panel, the transmissive image display unit 120 can display an image.

Since the thickness of the resin sheet 21 of the optical sheet 90 is thin (for example, the thickness is 1.5 mm or less), the optical sheet 90 can be easily applied to a thin notebook computer such as an ultra-fine notebook. Image display device 100.

When the thin resin sheet 21 is conveyed in the manufacturing process of the optical sheet 90, and the surface 21a is subjected to a specific function, it is important to fix the thin resin sheet 21 to the support sheet 40. In this regard, the description will be made in comparison with the case where the thin resin sheet 21 is not fixed to the support sheet 40.

The thin resin sheet 21 has a thin thickness and is therefore easily warped or easily deflected. Therefore, when the thin resin sheet 21 is not fixed to the support sheet 40 and the non-contact treatment for imparting a specific function to the surface 21a is performed, it is difficult to uniformly perform the non-contact treatment on the surface 21a. For example, in the case where the plasma treatment is used as an example of the non-contact treatment, if the thin resin sheet 21 is warped or deflected, the liquid repellency on the surface 21a becomes uneven. If the liquid repellency of the surface 21a becomes uneven, the light scattering point of the desired shape cannot be formed in the printing process step of the subsequent step. As a result, for example, when the optical sheet to be manufactured is used as a light guide plate, the brightness of the planar light emitted from the light exit surface of the light guide plate becomes uneven. In the case where the inkjet printing method is used as an example of the non-contact treatment, if the thin resin sheet 21 is warped or warped, the position at which the dots are formed with respect to the side of the surface 21a of the thin resin sheet 21 is deviated. Therefore, the dot pattern formed is deformed with respect to the desired pattern. As a result, for example, when the optical sheet to be manufactured is used as a light guide plate, the brightness of the planar light emitted from the light exit surface of the light guide plate is not generated as in the case of the plasma treatment. Uniformity.

On the other hand, when the thin resin sheet 21 is fixed to the support sheet 40 as in the manufacturing method described with reference to FIG. 1, warpage or deflection does not occur with a small thickness. Therefore, even if the support sheet 40 to which the thin resin sheet is attached is subjected to a process of imparting a specific function to the surface 21a and is a non-contact process, the surface 21a can be given a function in a desired state. For example, the liquid repellency can be uniformly imparted to the surface 21a by plasma treatment. When the liquid repellency is uniformly imparted to the surface 21a, the light scattering dots 80 of a desired shape are easily formed in the printing process step of the subsequent step. As a result, for example, when the optical sheet 90 to be manufactured is used as a light guide plate as shown in FIG. 9, it is easy to control the brightness of the planar light emitted from the light exit surface 90b to a desired brightness. In the case where the inkjet printing method is used as an example of the non-contact processing, when the thin resin sheet 21 is fixed to the support sheet 40, the position of the side with respect to the side of the surface 21a of the thin resin sheet 21 is not formed. It will deviate, so that the formed dot pattern can be formed into a desired pattern. As a result, for example, when the optical sheet 90 to be manufactured is used as a light guide plate as shown in FIG. 9, it is easy to emit the surface from the light exit surface 90b as in the case of the plasma processing. The brightness of the light is controlled to the desired brightness.

Further, when the support sheet 40 to which the thin resin sheet 21 is fixed and fixed is subjected to a plasma treatment as shown in FIG. 1, the dot pattern as a printed pattern is formed by the inkjet printing method while the support sheet 40 is conveyed in the same manner. The light scattering spot 80 of the desired shape can be formed into a further pattern as designed. As a result, for example, when the optical sheet 90 to be manufactured is used as a light guide plate as shown in FIG. 9, it is easy to further control the brightness of the planar light emitted from the light exit surface 90b to a desired brightness. .

When the thin resin sheet 21 is fixed to the support sheet 40, the fixing operation can be easily performed in the form of using a tape or an adhesive.

In the form in which the support plate 40 is provided with the positioning portion 41, the region of the surface 21a to which the functions of the plasma processing and the printing process, which have been exemplified, are subjected to processing, can be further carried out as designed.

In a form in which the arrangement region 40c in the surface of the support plate 40 is smaller than the thin resin sheet 21, one portion of the thin resin sheet 21 protrudes outward from the support plate 40. Therefore, it is easy to detach the thin resin sheet 21 or the optical sheet 90 from the support plate 40. Alternatively, when a serration process such as a process of imparting a concavo-convex shape to the side surface of the thin resin sheet 21 after the fixing step S2 is performed, the side surface on which the processing is performed may be exposed from the support plate 40. Therefore, the support plate 40 to which the thin resin sheet is attached can be conveyed by the transfer device 50, and the serration process can be easily performed on the side surface of the thin resin sheet 21. Since the thin resin sheet 21 is fixed to the support sheet 40, the serration processing is performed, so that the serration processing can be performed more precisely.

The various embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit and scope of the invention.

For example, in the manufacturing method shown in FIG. 1, the step of preparing the thin resin sheet 21 is described as a step of preparing the thin resin sheet 21. However, for example, the thin resin sheet 21 can be prepared by purchasing the thin resin sheet 21.

The function giving step S3 is only required to include at least one non-contact processing step. For example, in FIG. 1, the printing process step S3B may not be included. In this case, an optical sheet on which the liquid-repellent treatment has been applied to the surface 21a can be manufactured as a product. When the optical sheet as the product to which the liquid-repellent treatment has been applied to the surface 21a is used for the manufacture of the light guide plate, the optical sheet which has been subjected to the liquid-repellent treatment on the surface 21a should be the original sheet of the light guide plate of the light guide plate. Therefore, in Fig. 1, an optical sheet manufacturing method that does not include a printing process step is an example of a method of manufacturing a light guide plate original plate.

Alternatively, for example, in FIG. 1, the function imparting step S3 may not include the liquid dispensing processing step S3A. In this case, the ink may be dropped on the surface 21a in a state where the thin resin sheet 21 is fixed to the support sheet 40. Therefore, even if a light scattering point as a printing dot is formed by an inkjet printing method, it is easy to specify The printed pattern forms a light scattering spot.

Although the non-contact liquid-repellent treatment has been described as a specific example of the plasma treatment, as described above, the treatment using other energy rays may be employed. Further, it may be a treatment which can perform a liquid-repellent treatment in a non-contact manner, and is a treatment using a surface modifier as a liquid treatment agent, a treatment using chemical adsorption, or a treatment using graft polymerization on the surface of the material. .

Similarly, as the non-contact liquid-repellent treatment, a printing process using an inkjet printing method is exemplified, but for example, a printing process using a laser may be employed.

In the manufacturing method shown in FIG. 1, the function providing step S3 exemplifies a liquid-repellent processing step S3A and a printing processing step S3B including a processing step of performing processing while being conveyed in a non-contact manner. However, any of the processes may be a process step of a process step of performing processing without being carried out in a non-contact manner. For example, if the liquid dispensing process step S3A is a non-contact processing step, the printing process step S3B may also be a process using a stamper. Alternatively, if the printing process step S3B is a non-contact process step, the liquid-repellent process step S3A may be a process of roughening the surface 21a and imparting liquid-repellency to the surface 21a by adding irregularities to the surface 21a by hot pressing.

Examples of the non-contact treatment include a liquid dispensing process and a printing process. However, for example, instead of the liquid-repellent treatment, a hydrophilization treatment for imparting hydrophilicity to the surface 21a may be employed. Examples of the hydrophilization treatment include ultraviolet irradiation, plasma treatment, and the like. Ultraviolet irradiation can be performed using a low pressure mercury lamp, a metal halide lamp, or the like. Ultraviolet irradiation can be carried out in an air environment or in an ozone environment. As a plasma treatment, there is corona treatment. By performing such hydrophilization treatment on the surface 21a, an optical sheet having the surface 21a to which hydrophilicity is imparted can be produced. Moreover, when the printing process is further performed after the hydrophilization treatment to produce the optical sheet as the light guide plate, for example, the contact angle of the ink when the ink is dropped in the printing process step can be reduced. Therefore, a light guide plate having a flatter light scattering point can be manufactured.

In the form in which the support plate 40 has the positioning portion 41, an example of the positioning portion 41 is exemplified. The positioning rod 41-1. However, the positioning portion 41 is not particularly limited as long as the position of the thin resin sheet 21 with respect to the support plate 40 can be specified. Therefore, for example, as shown in FIG. 10, the positioning portion 41 may be a plurality of pins 41-2 that are discretely arranged along the edge portions 40a and 40b. Fig. 10 is a view showing another example of the positioning unit. Figure 10 is a view of the support plate 40 as viewed from its thickness direction.

When the thin resin sheet 21 is fixed to the support sheet 40, in addition to the method of fixing the thin resin sheet 21 to the support sheet 40 by the above-mentioned tape or adhesive, the thin resin sheet 21 can be attracted to the support. The method of the side of the board 40.

Fig. 11 is a view showing an example of a method of attracting a thin resin sheet to a support plate side and fixing a thin resin sheet to a support plate. In the method of fixing the thin resin sheet 21 to the support plate 40 by suction, the support plate 40 has at least one through hole 42. By the through hole 42 , the thin resin sheet 21 is sucked by the suction device 140 from the back surface of the support plate 40 , that is, the surface opposite to the surface on which the thin resin sheet 21 is mounted, whereby the thin resin sheet 21 is taken. It is fixed to the support board 40. The suction device 140 has, for example, a box shape, and is connected to an exhaust mechanism such as a vacuum pump, and is configured to be decompressible in the tank.

In the fixing method, for example, as shown in FIG. 11, as the conveying device 50, a belt conveyor 50-2 in which a plurality of through holes 50-2b are formed in the conveyor belt 50-2a can be used. In the form of the belt conveyor 50-2, the suction device 140 can be disposed between the upper and lower conveyor belts 50-2a in the belt conveyor 50-2. In FIG. 11, the suction device 140 is hatched to indicate the suction device 140. The support plate 40 is placed on the conveyor belt 50-2a41-1 so that the through hole 42 of the support plate 40 communicates with the through hole 50-2b formed in the conveyor belt 50-2a, whereby the thin resin can be used by the suction device 140. The sheet 21 is fixed to the support plate 40.

The example of the thickness of the thin resin sheet 21 is 1.5 mm or less, but the thickness of the thin resin sheet 21 is not limited to the illustrated thickness. The thickness of the thin resin sheet as the thin translucent sheet may be, for example, a thickness that causes warpage or deflection during transportation if the thin resin sheet is not fixed to the support sheet.

Further, as an example of the optical sheet used in the transmissive image display device or the like, a light guide plate is exemplified, but the optical sheet produced by the present invention may be a light diffusing plate or a light diffusing plate original plate.

[Industrial availability]

According to the present invention, it is possible to provide a method of manufacturing a thin optical sheet in which a main surface is more stably imparted with a specific function.

Claims (9)

A method for producing an optical sheet, which is a method for producing an optical sheet having a specific function on a main surface, and comprising the steps of: fixing a light-transmitting sheet to a support sheet; and fixing the light-transmitting property on one side The support plate of the sheet is conveyed in a specific direction, and a function imparting process for imparting at least one of the above functions is performed in a non-contact manner on the surface of the light-transmissive sheet which is the main surface. A method of producing an optical sheet according to claim 1, wherein the thickness of the light-transmitting sheet is 1.5 mm or less. The manufacturing method according to claim 1, wherein the function providing treatment system is a printing process for forming a specific printing pattern by a printing method, a liquid-repellent treatment for imparting liquid repellency to the surface, or the like, in order to impart light scattering properties to the surface. The surface imparts a hydrophilic hydrophilization treatment. The manufacturing method of claim 1, wherein the step of performing the at least one function imparting treatment in a non-contact manner comprises the steps of: performing a plasma treatment as a liquid-repellent treatment for imparting liquid repellency to the surface; and performing a printing process, This is to form a specific printed pattern by the inkjet printing method on the surface on which the liquid-repellent treatment has been carried out to impart light scattering properties to the surface. The manufacturing method of claim 1 or 2, wherein the function imparting treatment system is a plasma treatment for imparting liquid repellency to the surface, and the surface is opposite to the surface and used to generate the plasma The distance between the electrodes of the plasma in the treatment is 1.0 mm or more and 5.0 mm or less. The manufacturing method of claim 1 or 2, wherein the function is applied to a processing system for performing a printing process, wherein the surface is formed into a specific printing pattern by an inkjet printing method, The distance between the ink jet nozzle that ejects the ink in the inkjet printing method and the surface is 0.4 mm or more and 3.5 mm or less. The manufacturing method according to any one of claims 1 to 6, wherein the support plate has a positioning portion for fixing the light-transmitting sheet to a specific position on the support plate. The manufacturing method according to any one of claims 1 to 7, wherein the arrangement area of the light-transmitting sheet on the support plate is smaller than the size of the light-transmitting sheet. The manufacturing method according to any one of claims 1 to 8, wherein the support plate has a warpage amount of 0.1 mm or less, and the amount of warpage is such that the support plate having a length of 1 m and a width of 1 m is placed. The maximum value of the distance from the above horizontal plane to the bottom of the support plate in the horizontal direction in the horizontal plane.