JPH07117144A - Production of light guide plate for plane light source - Google Patents

Abstract

PURPOSE:To make simple molding processing requiring no expensive mold possible by placing a shaping sheet wherein a microlens molding uneven shape is formed on the surface of a resin sheet in a mold and injecting a resin into the mold to solidify the same before peeling a shaping sheet. CONSTITUTION:When a light guide plate 4 is molded by injection molding using a shaping sheet 1 and not preforming for example, a three-dimensional crosslinked resin layer is provided on a base sheet and an uneven shape is formed to the surface of the light guide plate 4 by a casting method. The uneven shape is formed so as to be same but reverse to the uneven shape of a lens to be formed. This shaping sheet l is set to the interior of the mold of an injection molding machine so that a female mold 5 is separated into a flat mold and an O-shape mold and the shaping sheet 1 is held between both of them and the uneven shape of the shaping sheet 1 is fixed to the bottom surface of the female mold 5 so as to be directed toward a cavity. In this state, mold clamping is performed and, for example, a polycarbonate resin is injected into the cavity 8 and cooled to be demolded and, further, the shaping sheet 1 is peeled to obtain the light guide plate 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmissive display device such as a transmissive liquid crystal display device (transmissive LCD), a back light source used for lighting advertisements, measuring instruments and the like, and a light guide plate surface for a light source. The present invention relates to a method for producing a transparent transparent resin plate for a backlight, which is faithful to a design shape and has excellent optical characteristics, by mass-producing it with good reproducibility, by forming an uneven shape on the surface of the light plate.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a transparent resin plate for a backlight, in which an uneven shape is directly formed on the surface of a light guide plate used for a back light source, an illumination light source, etc., Japanese Patent Laid-Open No. 62-2785.
No. 04, JP-A No. 62-278505, there is known a method of molding with a mold having an uneven shape on the mold itself. This method is used to form a fine lens array such as a lenticular lens or a fly's eye lens for converging or diffusing the light source light on the surface of the light guide plate of the edge light surface light source. It is a method of injecting a transparent resin into a mold, solidifying it, and then removing the mold. In the case of this method, (1) it takes a lot of time and money to manufacture the mold, so that it costs a lot of money to manufacture many types of microlens shapes, and it is difficult to meet the deadline. (2) When manufacturing one lens shape and then switching to another lens shape, the mold itself is exchanged, which requires a lot of setup time and labor. (3) In particular, when forming a minute lens on a curved surface, it is difficult to process a lens shape having a fine and desired shape on the curved mold surface. (4) When a monomer or prepolymer of a three-dimensional cross-linking curable resin is injected into the mold and solidified by cross-linking curing (so-called reactive injection molding), demolding is performed by the anchoring effect of the minute lens shape part. Hard to do. (5) If a hard resin film is to be formed on the microlens array after molding the lens shape, the lens shape is filled and the lens effect is lost. However, there were drawbacks such as the above, which was a problem.

[0003]

SUMMARY OF THE INVENTION Under the circumstances, the present invention does not require an expensive mold having a concavo-convex shape on the surface of the molding die itself, and can easily save labor and time. The present invention provides a method for forming a microlens array on the surface of a light guide plate, which can be applied to a curved light guide plate by using a molding method.

[0004]

According to the present invention, a light guide plate for a surface light source having a microlens array on its surface is manufactured by injecting a resin into a cavity of a molding die, solidifying the resin liquid, and then removing the mold. A method for forming a molding sheet, comprising a resin sheet, and a concave-convex shape having the same shape as the microlens array and the reverse concave-convex shape formed on the surface of the resin sheet, with the concave-convex portion facing the cavity side of the molding die. After being placed inside, the resin is injected into the cavity, the resin is solidified, and then the mold release sheet is released from the molded resin plate and the light guide plate for surface light source is manufactured. is there. By forming an uneven shape of the desired unevenness of the microlens array and the reverse concavo-convex shape on the surface of the patterning sheet, a light guide plate for a surface light source having a microlens array is produced by using this as a master mold. With the concave-convex portion of the shaping sheet having a predetermined concave-convex shape facing the cavity side and being placed in the molding die, resin is injected into the mold,
The resin is solidified, the mold is removed, and the shaping sheet is peeled from the molded resin plate to manufacture a surface light source light guide plate. In the method for manufacturing a light guide plate for a surface light source of the present invention, even if the same mold, for example, a mold having a smooth surface, is used, a mold having concave and convex portions of various shapes corresponding to a microlens array of various shapes is formed. By using the sheet, a light guide plate for a surface light source having a minute lens array of a predetermined shape can be manufactured by using the sheet as a master. It is not necessary to form the molding die into the desired shape each time, as compared with the conventional method in which the concavo-convex shape that matches the desired lens shape is formed on the molding die itself. Just replace it. Further, in the method for manufacturing a light guide plate for a surface light source of the present invention, a hard film made of a three-dimensional cross-linking cured resin that can be peeled from the patterning sheet is disposed on the uneven surface of the patterning sheet. While molding, only the shaping sheet is peeled off, and the concavo-convex portion of the minute lens array made of a hard film is integrated on the surface of the molded resin plate. As shown in FIG. 5 (1), a hard film made of a three-dimensional cross-linking curable resin that can be peeled from a shape-imparting sheet is transferred onto the surface of a molded resin plate,
The microlens array made of a hard film is integrally formed on the surface of the resin plate. Then, the method for manufacturing a surface light source light guide plate of the present invention, if necessary, an adhesive layer is provided on the surface of the hard film described above, and only the shaping sheet is peeled off at the time of demolding and molding. A hard film having concave and convex portions of a minute lens array is adhered and integrated on the surface of the resin plate. As shown in FIG. 5 (2), an adhesive layer is previously provided on the hard film so that the adhesive layer is interposed between the hard film and the molded resin plate, and the hard film and the adhesive layer are molded from the shaping sheet side. The microlens array made of a hard film is integrally formed on the surface of the resin plate via the adhesive layer. Note that, hereinafter, a sheet obtained by providing the above-mentioned shaping sheet with a hard film or a hard film and an adhesive layer or the like to be transferred to a resin plate to be molded is referred to as a transfer sheet.

The method of manufacturing a light guide plate for a surface light source according to the present invention is a method of manufacturing a light guide plate for a surface light source having a microlens array on the surface, which is the same as the microlens array on the surface of the resin sheet. A microlens array is formed on the surface of a transparent resin plate by hot-pressing a shape-imparting sheet formed by forming an uneven shape of shape-reversed shape so that the uneven shape portion contacts one surface of the transparent resin plate. . In the method for manufacturing a light guide plate for a surface light source of the present invention, a patterning sheet having an uneven shape is used, and a microlens array is directly formed on a transparent resin plate by heat pressing. In the same manner as described above, a hard film made of a three-dimensional cross-linking curable resin that can be peeled from the patterning sheet is provided on the uneven surface of the patterning sheet, and the patterning sheet is arranged so that the hard film side is in contact with one surface of the transparent resin plate. By heating and pressing, the hard film having the concave and convex portions of the microlens array is transferred to the transparent resin plate and formed integrally. Then, if necessary, an adhesive layer is provided on the above-mentioned hard film, and the concavo-convex portion of the minute lens array made of the hard film is adhered and integrated with the transparent resin plate to be formed.

Here, the base sheet for the shaping sheet used is one that is easy to remove from the mold and is easily peeled off from the resin plate to be molded, and has strength as a shaping sheet.
A material that can be applied to the molding treatment is selected, but linear polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polypropylene, polyolefins such as polymethylpentene, linear polyamides such as nylon 6 and nylon 66, and polyvinyl chloride. It is made of a material such as polyarylate and polyimide, and has a thickness of about 12 to 200 μm and is flexible. In the case of preforming the shaped sheet, the base sheet is made of a thermoplastic resin.

Further, in order to form the uneven shape of the shape-imparting sheet, it can be directly formed on the base material sheet by hot pressing, casting (casting) or the like, but preferably,
A three-dimensional crosslinked resin layer is provided on the base material sheet, and an uneven shape is formed on the surface by a casting method. The concavo-convex shape is an inverse concavo-convex shape having the same shape as the lens shape to be formed.
Square prism linear array (Fig. 6 (1)), convex or concave lenticular lens (Fig. 6 (2)), random grain, matte shape such as satin (Fig. 6 (3)), pyramidal lens array (Fig. 6)
(4)), a hemispherical lens array (fly-eye lens), a Fresnel lens, and the like. Examples of the casting method using a three-dimensional crosslinked resin are disclosed in JP-A-3-223883, US Pat. No. 4,576,850 and the like. In this case, an easy-adhesion primer is previously formed on the base material sheet, if necessary. As a primer for forming the uneven shape of the shape-imparting sheet, a two-component curable coating material containing an acrylic polyol as a main component and an isocyanate-based curing agent can be mentioned. It is not limited to this as long as the adhesive force with the sheet is sufficient. Examples of the three-dimensional cross-linking resin that forms the uneven portion include thermosetting resins and ionizing radiation curing resins. As the thermosetting resin, a phenol resin, a urea resin, a diallyl phthalate resin, a melamine resin, a guanamine resin, an unsaturated polyester ketone resin, a polyurethane resin, an epoxy resin, an aminoalkyd resin, a melamine-urea co-condensation resin, a silicon resin, There are polysiloxane resins and the like, and if necessary, a crosslinking agent, a curing agent such as a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier, an extender pigment and the like are added. As the curing agent, usually, isocyanate, organic sulfonic acid or the like is used for polyester resin, polyurethane resin, amine is epoxy resin, peroxide such as methyl ethyl ketone peroxide, radical initiator such as azobisisobutyl ester. Often used for unsaturated polyester resins. The ionizing radiation curable resin, acryloyl group in the molecule, a polymerizable unsaturated bond such as methacryloyl group, a thiol group, or a prepolymer having an epoxy group, an oligomer, and / or a composition prepared by appropriately mixing a monomer To use. As these resin systems, urethane acrylate, polyester acrylate, acrylate such as epoxy acrylate, urethane methacrylate, polyester methacrylate, methacrylate such as epoxy methacrylate, silicon resin such as siloxane, unsaturated polyester,
Examples thereof include epoxy. Further, 1 to 70 of the following ionizing radiation non-curable resins is used for at least one of the prepolymer, oligomer and monomer for controlling the physical properties such as flexibility and surface hardness of the cured product. The mixture can be used by weight, preferably 5 to 50% by weight. As this ionizing radiation non-curable resin, a thermoplastic resin such as urethane-based, fibrin-based, polyester-based, acrylic-based, butyral, polyvinyl chloride, or polyvinyl acetate can be used, and in particular, it is flexible. Fiber-based, urethane-based and butyral are preferred. Particularly when it is cured by ultraviolet rays, as a photopolymerization initiator in the ionizing radiation curable resin composition, acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime ester, tetramethylmedium monosulfide, thioxanthones, and /
Alternatively, n-butylamine, triethylamine, tri-n-butylphosphine or the like may be mixed and used as the photosensitizer. Here, the ionizing radiation means an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing and cross-linking molecules, and usually ultraviolet rays and electron beams are used. Ultra-high pressure mercury lamp, high pressure mercury lamp,
Low pressure mercury lamp, carbon arc, black light lamp,
A light source such as a metal haloid lamp is used.

As a method of molding the light guide plate, there are injection molding, reactive injection molding (RIM molding), casting (casting) and hot pressing. In particular, a detailed description will be given below by taking an ordinary injection molding method of injecting a hot-melt resin as an example. Basically, the first method as shown in FIG. 1 in which a shaping sheet or a transfer sheet is inserted into a cavity between molding dies without preforming,
The second method as shown in FIG. 2 in which a shaping sheet or a transfer sheet is preformed so as to be closely adhered along the surface of the molding die is applied to the molding of the light guide plate. The first method is used when the shape of the light guide plate is a flat plate or a curved surface and has a low curvature and the drawing amount of the sheet during molding is small. As shown in FIG. 1, a preferable mode of the molding die is that the female die 5 is divided into a flat plate die and a square die, and the shaping sheet 1 is sandwiched between the two.
This is a method of fixing the shaping sheet to the bottom of the female mold. By doing so, the deformation of the shaping sheet at the time of injection molding and shaping can be minimized, so that the shape and dimensions of the microlens array can be faithfully reproduced as designed. The second method is
It is used when the shape of the light guide plate is a curved surface, especially when the curvature is large and the drawing amount of the sheet during molding is relatively large. In this method, as shown in FIG. 2, the shaping sheet is heated and softened in advance, and is adsorbed to the surface shape of the molding die (usually female mold) by vacuum molding, pressure molding, or vacuum pressure molding so as to follow. . For heating, it is also possible to use a method in which a sheet is suction-adhered to the surface of a hot plate (board) and conduction heating is performed as described in Japanese Patent Publication No. 9647/1992, but unevenness is formed in a thin film. In the case of a shaped sheet having a surface, a method of fixing the shaped sheet at a certain distance from the heating plate and heating with radiant heat from the heating plate is preferable. In both of the first method and the second method, it is a uniform optical characteristic that a weld line is generated in the injection resin, residual air bubbles are contained, a flow mark is generated, or a gate mark is generated. Is not preferable in obtaining As one mode of the die for preventing these, as shown in FIG. 8, the molten injection resin exiting the gate (gate) is once collided with the pressure relaxation barrier to reduce the pressure and speed and to make them uniform. In addition, it is preferable that the cavities are filled from one time toward the other end. Therefore, a gate is provided in a direction orthogonal to the longitudinal direction of the light guide plate-shaped cavity (the direction in which the resin flows and is filled). Regarding the design of such a molding die, it has already been proposed in Japanese Patent Laid-Open No. 4-316814 for the purpose of preventing the transfer pattern of the transfer sheet from melting and flowing due to the pressure of the injection resin. Is also useful in the present invention for obtaining uniform optical properties. In the case of the above-mentioned ordinary injection molding, a resin (liquid form) obtained by heating and melting a thermoplastic resin such as acrylic, polycarbonate, polystyrene, and acrylonitrile styrene is used.
The solidification in this case is performed by cooling.

In the case of RIM molding or casting, a monomer and / or prepolymer produced by crosslinking or polymerizing a thermosetting resin or an ionizing radiation curing resin is used. Select a material that is transparent when both solidify. As the thermosetting resin, phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea co-condensation resin, silicon resin, There are polysiloxane resins and the like, and if necessary, a crosslinking agent, a curing agent such as a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier, an extender pigment and the like are added. As the ionizing radiation curable resin, a composition in which an acryloyl group in the molecule, a polymerized unsaturated bond such as a methacryloyl group, a thiol group, or a prepolymer having an epoxy group, an oligomer, and / or a monomer is appropriately mixed. To use. For these resin systems,
Examples thereof include acrylates such as urethane acrylate, polyester acrylate, and epoxy acrylate, urethane methacrylate, polyester methacrylate, and methacrylate such as epoxy methacrylate, silicon resin such as siloxane, unsaturated polyester, and epoxy. In the case of RIM molding, the thermosetting resin or ionizing radiation curable resin is injected into the cavity formed by a female mold and a male mold, and in the case of casting, a gravure coat, It is applied by roll coating or the like, and after that, it is crosslinked and hardened, and then solidified. Select a releasable resin system from the shaping sheet. In order to improve the releasability in any of the above-mentioned molding methods, a release agent such as a silicone resin, a fluorinated resin, or a wax may be added to the uneven layer of the hard film and / or the shaping sheet. A preferred embodiment is that the release agent is added to the concave-convex shaped layer side of the shaping sheet so as not to impair the transparency of the light guide plate molded body. As the release agent, a preferable one is a polyfunctional or monofunctional acrylate, a crosslinkable monomer such as methacrylate, or a prepolymer or oligomer in which an organic silicon group is bonded to the side chain of the molecule, and the uneven layer is used. If you try to crosslink with, molding,
It is good without bleeding on the surface of the light guide plate at the time of imprinting and causing white turbidity and interference gloss. Also, adjacent to the hard film,
It is also possible to disperse a transparent resin binder particle diameter of 0.5 μm to 20 μm and a delusterant fine powder to provide a delustering layer, or to disperse the delusterant in a hard film. As the matting agent, inorganic substances such as barium sulfate, zinc white, glass, silica and calcium carbonate, and organic polymers such as acrylic resin, polyurethane resin and polyethylene carbonate are used. in this way,
By providing the matting agent addition layer, the light emitted from the light guide plate can be uniformly and isotropically diffused. Of course, if the light guide plate itself does not need a diffusion layer, this can be omitted. The adhesive layer provided on the hard film is a transparent resin, usually an acrylic resin such as alkyl polyacrylate or alkyl polymethacrylate, vinyl resin such as vinyl acetate, vinyl acetate / vinyl chloride copolymer, or the like. ,polystyrene. Ionomer,
An isocyanate compound or the like, or a mixture of two or more kinds, is selected from those having good adhesion to the hard film and the light guide plate resin and having an appropriate refractive index.

Further, in the method for manufacturing a light guide plate for a surface light source according to the present invention, the shaping sheet or a transfer sheet having a hard film transfer layer is inserted into the surface of the shaping die, and is opposed to the shaping sheet of the shaping die. A transfer sheet having a light reflection layer, an EL (electroluminescence) layer, etc. is inserted into the surface on the side where the light is applied, the resin liquid is injected and filled, and the resin sheet is solidified. It is also possible to form an array or a microlens array and a hard film, and directly form a light reflection layer, an EL (electroluminescence) layer or the like on the back surface thereof. (FIG. 7 (2)) As the light reflection layer, a specular reflection layer made of a metal thin film such as aluminum or chrome, or a dot pattern light diffusion reflection layer on the side close to the light guide plate as shown in FIG. 7 (1), The thing which consists of a specular light reflection layer on the outer side is mentioned. As the light diffusion layer, an ink in which a light diffusion agent powder having a particle size of 0.5 to 20 μm, such as titanium dioxide, calcium carbonate, or zinc oxide, is dispersed in a transparent resin binder is printed in a dot pattern by silk screen printing or the like. Then make. As the dot pattern, as disclosed in Japanese Patent Laid-Open No. 1-245220, the area near the light source at the end on the light guide plate side has a smaller area, and the area gradually increases as the distance from the light source increases. It is preferable to use a pattern that equalizes that the brightness of the near part is high and the brightness of the distant part is low. Also, E
As the L (electroluminescent) layer, the adhesive layer, the transparent electrode, the phosphor layer, the light reflection electrode layer, and the protective layer are arranged from the side closer to the light guide plate. The transparent electrode layer is formed by depositing tin oxide, indium oxide, tin oxide-doped indium (ITO) or the like by vacuum deposition, sputtering or the like. The phosphor layer has ZnS (zinc sulfide), SrS (strontium sulfide), SeS (selenium sulfide), CaS (calcium sulfide), etc. as a matrix, and Cu, Mn, TbF ₃ , Ce, and
A material doped with Eu, Sm, PrF ₃ , TmF ₃ or the like is used. As the formation of the fluorescent material layer, the fluorescent material itself is vapor-deposited,
A film is formed by sputtering or the like, or a fluorescent substance dispersed in a binder of a transparent and insulating dielectric resin is applied or printed to form a film. Examples of the binder resin include acrylic resin and polyvinyl carbazole. As the light reflecting electrode layer, aluminum, chromium, silver or the like is formed by vacuum vapor deposition, sputtering or the like. Although the protective layer is not essential from the viewpoint of the light emitting effect of EL, it protects the EL layer from moisture and abrasion, and further, the peelability of the EL layer (transparent electrode layer, phosphor layer, light reflecting electrode layer) from the support sheet. It is necessary to get good. Specifically, there are the above-mentioned heat or ionizing radiation curable resins, polyvinylidene fluoride, fluorine resins such as vinyl fluoride, ethylene / vinyl alcohol copolymers and the like. The adhesive layer is not essential from the viewpoint of the light emitting effect of the EL, but is necessary in order to improve the adhesive strength between the EL layer and the light guide plate resin. Specifically, it may be selected from the same materials as those used for transferring a hard film.

[0011]

In the light guide plate method of the present invention, with the above-described structure, it is possible to manufacture light guide plates of various shapes with a minute lens array by using the same molding die and simply changing the shaping sheet. There is. Since it is only necessary to replace with a shaping sheet corresponding to the lens shape in advance, it is possible to easily manufacture various lens shapes. Further, in the method for manufacturing a light guide plate of the present invention, a resin film formed by forming a cured film made of a three-dimensional cross-linking cured resin that can be peeled from the patterning sheet on the uneven surface of the patterning sheet. The concave and convex portions of the minute lens array made of a hard film are integrated in the, and the lens shape of the light guide plate is better than the case where the lens shape is provided only by the molding resin by this hard film. It makes it possible to manufacture expensive products. If necessary, an adhesive layer is provided on the surface of the cured film described above, so that the concave and convex portions of the minute lens array made of a hard film can be reliably bonded and integrated with the molded resin plate. It is possible. In the method for manufacturing a light guide plate of the present invention, since the lens shape is formed on the surface of the light guide plate using the shape-imparting sheet as the master mold, the shape-imparting sheet is preformed before injection molding with the molding die. It is possible to manufacture a light guide plate having a curved uneven shape by bending it in advance.

[0012]

Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 4 is a schematic view of a manufacturing apparatus for explaining a manufacturing process of a shaping sheet, and FIG. 1 is a schematic view for explaining a method of molding a light guide plate by injection molding without using preforming. . First, the manufacturing process of the shaped sheet will be described with reference to FIG. First of all, biaxially stretched PE with easy adhesion on one side
A film substrate 40 (HP-7, Teijin) made of T (polyethylene terephthalate) and having a thickness of 75 μ was passed between the primer coating roll 42 and the impression cylinder roll 43. The isocyanate-cured urethane primer 41 was transferred from the ink pan to the coating roll, and this transferred primer was further applied from the coating roll to one side of the film substrate on which the uneven shape is formed and transferred. Next, the film base material coated with the primer is dried in the drying zone 44, and then the film base material 40 and the roll intaglio plate 46 in which the ionizing radiation curable resin easy 45 is supplied and filled in the recessed portion by the nozzle coating device. , Between the nip rolls 47a and 47b consisting of at least two, on the side of the film base material on which the primer is applied, which is irradiated with ionizing radiation by the ionizing radiation irradiation device 48 to cure the ionizing radiation curable resin. In addition, it was integrated with the film substrate.
After passing through the final nip roll 47b, the film base material was peeled off from the roll intaglio plate to obtain an imprinted film sheet 49 having an uneven shape. As the ionizing radiation curable resin for forming the uneven shape on the film substrate, a resin containing a urethane acrylic polyfunctional prepolymer as a main component was used. A chemical mat medium (The Inktech Co., Ltd.) was used as a primer for increasing the adhesiveness between the base film and the resin, and an XEL curing agent (The Inktec Co., Ltd.) was used as a curing agent. As the ionizing radiation irradiation device using the ultraviolet irradiation apparatus according to a high-pressure mercury lamp 160 W / cm ³ 2 lamps of there ozone. As the roll intaglio, a prism shape having a period of 50 μm, a kamaboko shape of 200 μm,
A mat-shaped solid plate by sandblasting # 200 was used one by one to prepare a corresponding shaped film sheet. Matching the shape of the roll intaglio
A shaped film sheet as in (1) to (3) was obtained. Next, each of the obtained shape-imparting film sheets was set in a mold of an injection molding machine and injection-molded without pre-molding to manufacture a light guide plate. This will be described with reference to FIG. As shown in (1), the female die 5 is divided into a flat plate type and a square type, and the pattern forming sheet 1 is sandwiched between the two.
With the shaping sheet fixed to the bottom of the female mold 5, with the mold clamped as shown in (2), after injecting the polycarbonate resin as shown in (3), after cooling, as shown in (5). After removing the mold, the patterning film sheet was peeled off as in (6) to obtain a light guide plate 6. The light guide plates having the shapes corresponding to the respective shape-imparting film sheets thus obtained were all excellent in quality.

A second embodiment of the present invention will be given. Using a film substrate having a thickness of 25 μm and made of 920 molding PET (polyethylene terephthalate) manufactured by Dia foil Co., Ltd., and in the same manner as in Example 1, each of the shaped film sheets as shown in FIGS. 6 (1) to 6 (3) was used. Obtained. Next, each of the obtained shape-imparting film sheets was set in a mold of an injection molding machine, pre-molded, and then injection-molded to mold a light guide plate. FIG. It is a figure. Hereinafter, description will be given with reference to FIG. First, as in (1), the shaping sheet 11 was inserted between the female mold 15 and the male mold 16 so that the concavo-convex shape faced the cavity side. At this time, the heating device 27 for softening the shaped film sheet is still in the standby position apart from both molds. Next, as in (2), the heating device 27 is sandwiched between the shaping sheets to face the female mold.
The shape-imparting sheet was heated while being moved to the heating position.
Next, when the shaping sheet is sufficiently softened in the state of (2), vacuum suction from the female die 15 and heating plate 29 are performed as in (3).
The shaped sheet was formed along the surface of the female mold by pressure and air pressure from, and was brought into close contact with each other to perform preforming. Next, as shown in (4), after returning the heating device 27 to the standby position so as not to interfere with the opening and closing of the male and female dies, the male and female dies are clamped to form a cavity, and the gate ( The molten resin 19 was injected and filled from the gate) 17. Then, after the molten resin was cooled and solidified, both molds were opened as shown in (5), and a product in which the shaping sheet and the resin molding (light guide plate) were integrated was removed from the mold. After demolding, the patterning sheet 11 was peeled off as in (6) to produce the light guide plate 14. The heating device 27 includes a hot platen (panel heater) 29 and a peripheral wall 30 that surrounds the peripheral edge of the hot plate 29 once in a bank shape, and the peripheral wall keeps the shaping film sheet at a predetermined distance from the hot plate. Prevents the mold sheet from being displaced or deformed during heating and preforming. The electric heater 28 serving as a heat source is provided in the heating plate.
Etc. are buried. The hot platen has good thermal conductivity, iron, similar metal, infrared radiation efficiency and heat resistant ceramics,
Alternatively, it consists of a complex of these. During heating and preforming, the shaping sheet is sandwiched between the peripheral wall and the female parting surface to prevent the sheet from being displaced or deformed. An O-ring is embedded on the female parting surface to help keep the sheet in close contact. Further, in the above-mentioned preforming, vacuum suction from the female mold and compressed air pressurization from the heating plate may be possible with only one of them, and either one or both may be used in combination as required.

A third embodiment of the present invention will be described. Example 3 is
Shaped film sheet 2 obtained in the same manner as in Example 1.
1 is obtained by molding the light guide plate 24 with a hot press machine, and FIG. 3 is a schematic process diagram of the third embodiment. As shown in FIG. 3, a shaped film sheet obtained in the same manner as in Example 1 was used as a transparent resin plate 21 (Mitsubishi Acrylite) made of acrylic resin.
The light guide plate 24 having a thickness of 3 mm and subjected to press working with the heating press machines 25 and 26 was manufactured to have a shape suitable for each shaping film sheet.

[0015]

EFFECTS OF THE INVENTION With the above-described structure, the present invention is capable of forming a microlens array of various shapes on the surface of a light guide plate simply by exchanging a shaping sheet.
This makes it possible to provide a method that saves cost and time without the need to manufacture an expensive mold in which the concavo-convex shape is formed on the molding die itself. INDUSTRIAL APPLICABILITY According to the present invention, by preparing a shaping sheet having a predetermined shape in advance, only one molding die can be used, and the manufacturing of a light guide plate having a certain lens shape is completed, and the light guide plate having another lens shape is manufactured. Even when carrying out, it is possible to reduce the setup time and labor. The present invention can be manufactured by performing pre-molding and then injection-molding even when forming a minute lens on a curved surface, and can process a desired minute lens shape on a curved light guide plate. I am trying. Further, in the present invention, a light guide plate provided with a lens shape made of a hard film can be produced by providing a hard film on the concave-convex shaped portion of the shaping sheet. The surface durability and wear resistance are better than when the lens shape is provided, and the lens shape does not collapse compared to when a hard film is coated on the lens shape. It is possible to make things. Further, in the present invention, it is not necessary to provide the mold itself with a concavo-convex shape conforming to the lens shape. For example, the cavity side of the mold can be made to have a smooth surface, and the light guide plate can be easily demolded. it can. Even when injecting the three-dimensional crosslinking effect resin into the molding die and crosslinking and solidifying the resin, the molding sheet can be easily peeled off after demolding by selecting a flexible and flexible molding sheet.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a method for manufacturing a light guide plate by injection molding without preforming according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a manufacturing method for manufacturing a light guide plate by injection molding after preforming according to the second embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining the manufacture of a light guide plate by a heating press according to a third embodiment of the present invention.

FIG. 4 is a schematic view of the manufacturing process of the shaped sheet of the present invention.

FIG. 5 is a diagram for explaining a shaping sheet and a light guide plate corresponding to the shaping sheet according to the present invention.

FIG. 6 is a diagram of a patterning sheet according to the present invention.

FIG. 7 is a diagram of a light guide plate manufactured by the manufacturing method of the present invention, and a usage example thereof.

FIG. 8 is a cavity of a molding die according to a second embodiment of the present invention. Illustration of another example of a gate

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1, 21 21 Shaped sheet 2, 12, 22 Sheet base material 3, 13, 23 Concavo-convex shape part 4, 14, 24 Light guide plate 5, 15 Female type 6, 16 Male type 7, 17 Gate gate 8, 18 Cavity 9, 19 molten resin 25 upper surface press 26 lower surface press 27 heating device 28 electric heater 29 hot platen 30 peripheral wall 31 intake air 32 compressed air 40 base material sheet 41 primer 42 coating roll 43 impression cylinder 44 drying zone 45 resin liquid 46 roll intaglio 47a, 47b Nip roll 48 Ionizing radiation irradiation device 49 Shaped sheet 50 Concavo-convex shaped portion 51 Shaped sheet 52 Base material sheet 53 Concavo-convex shaped portion 54 Hard film 54a Hard film after transfer 55 Adhesive layer 55a Adhesive layer after transfer 56 Transparent resin Forming plate 57 Light guide plate

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Claims (6)

[Claims] 1. A resin is injected into a cavity of a molding die,
A method of manufacturing a surface light source light guide plate having a microlens array on the surface after solidifying the resin liquid, wherein a concavo-convex shape having the same shape as the microlens array and the reverse concavo-convex shape is formed on the surface of the resin sheet. The formed sheet is placed in the molding die with the concave-convex portion facing the cavity side of the molding die, resin is injected into the cavity, the resin is solidified, and then the molded sheet is removed. A method of manufacturing a light guide plate for a surface light source, which comprises molding and releasing a shaping sheet from a molded resin plate. 2. A hard film made of a three-dimensional cross-linking curable resin, which can be peeled from the shaping sheet, is provided on the uneven surface of the shaping sheet according to claim 1, and is removed from the shaping sheet at the same time. Only the sheet is peeled off, and on the molded resin plate surface,
A method for manufacturing a light guide plate for a surface light source, characterized in that a hard film having concave and convex portions of a minute lens array is integrated. 3. The adhesive layer according to claim 2, wherein an adhesive layer is provided on the surface of the cured film, and only the shaping sheet is peeled off at the time of demolding, and the concavo-convex portion of the minute lens array is formed on the surface of the molded resin plate. A method for manufacturing a light guide plate for a surface light source, which comprises integrally bonding a hard film having: 4. A method of manufacturing a light guide plate for a surface light source having a microlens array on the surface, which comprises forming a concavo-convex shape having the same shape as the microlens array on a surface of a resin sheet. A method for manufacturing a light guide plate for a surface light source, comprising forming a fine lens array on the surface of a transparent resin plate by hot-pressing a sheet so that the irregularities contact one surface of the transparent resin plate. 5. The shape-imparting sheet according to claim 4, wherein a hard film made of a three-dimensional cross-linking curable resin that can be peeled from the shape-imparting sheet is provided on the uneven surface, and the shape-imparting sheet is transparent on the hard film side. It is characterized by forming a minute lens array on the surface of the transparent resin plate by integrating a hard film having concave and convex portions of the minute lens array on the transparent resin plate by heating and pressing so as to contact one surface of the resin plate. Manufacturing method of light guide plate for surface light source. 6. The microlens array according to claim 5, wherein an adhesive layer is provided on the surface of the cured film, and the shaping sheet is heated and pressed so that the adhesive side is in contact with one surface of the transparent resin plate. A method for manufacturing a light guide plate for a surface light source, characterized in that a hard film having uneven portions of (1) is bonded and integrated with a transparent resin plate to form a microlens array on the surface of the transparent resin plate.