JP2004163498A - Method for forming slope, method for manufacturing optical film, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing and obtaining a thin and lightweight optical film which has a light emitting means formed by dispersing and distributing fine structure recessed parts having excellent sharpness of groove vertices and surface precision of slopes thereon. <P>SOLUTION: In the method for manufacturing the optical film, laser light (1) is radiated through a projection mask for controlling the size of transmitted light (4), and the resultant light irradiates the polymer film (5) in order to etch the polymer film (5). The projection mask is constituted of partial masks (2, 3) which form a laser light transmission part for making the shape of the transmitted laser light quadrilateral. The state of the laser light transmission part is changed from a state for making the laser light shape into the quadrilateral to a closed state formed by moving the partial masks in parallel but in opposite directions along its short side direction to form a recessed part with a triangular cross-sectional shape on the polymer film. A plurality of discontinuously distributed recessing parts each of which comprises a steep slope and a gentle slope are formed on the surface of the polymer film by repeating the above process to close the rectangular laser light transmission part along its short side direction. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a slope forming method capable of forming a recess having a triangular cross section having excellent sharpness of a groove apex and surface accuracy of a slope, and a thin and lightweight liquid crystal display device which efficiently converts a light beam in a horizontal direction into a light path in a vertical direction. The present invention relates to a method for manufacturing an optical film that can be formed.
[0002]
BACKGROUND OF THE INVENTION
Conventionally, there has been known a front light type reflection type liquid crystal display device in which a side light type light guide plate having a light emitting means having a stripe-shaped prism structure is arranged on the viewing side surface of a liquid crystal display panel (Japanese Patent Laid-Open No. Hei 11-1999). -250715). The formation of such light emitting means has been performed by a mechanical processing method in which the surface of the plate is cut with a diamond tool or the like, or a dry etching method in which a triangular projection mask is scanned.
[0003]
However, the stripe-shaped prism structure interferes with the pixels of the liquid crystal panel and causes moiré, which tends to reduce display quality. In the front light type where the light guide plate is located in front of the liquid crystal panel, the surface reflection of external light causes the liquid crystal to reflect. The display contrast tends to decrease, and defects such as scratches on the light guide plate are noticeable, and the use of the light guide plate increases the bulk and weight.
[0004]
Technical Problems of the Invention
In view of the above, the present inventors have conceived of a method using a light emitting means in which a large number of minute concave portions (grooves) are dispersed and distributed. According to this, it is possible to easily overcome the above-described moiré problem, surface reflection problem, visual obstruction problem due to defects, bulky / heavy weight problem, and the like.
[0005]
However, there has been a problem that it is difficult to manufacture a light emitting means in which such minute concave portions are dispersed and distributed by a conventional method. In other words, it is extremely difficult to form an intermittent structure in which minute concave portions are precisely dispersed and distributed at predetermined positions by machining, and it is extremely difficult to form an intermittent structure of a concave portion having a constant cross-sectional shape even by a method using a diamond grindstone. Have difficulty. Further, even in the dry etching method in which a triangular projection mask is scanned, the sharpness of the apex of the groove in the concave portion and the surface accuracy of the inclined surface are poor and the light emitting means is likely to cause a decrease in luminance.
[0006]
In view of the above, the present invention is directed to a thin and light-weight device having a light emitting unit for distributing and distributing fine concave portions having excellent sharpness at the apex of a groove or surface accuracy of a slope with good positional accuracy and efficiently converting light incident in a horizontal direction into an optical path in a vertical direction. Another object of the present invention is to develop a method for obtaining such an optical film.
[0007]
[Means for solving the problem]
The present invention provides a method of irradiating a polymer film by irradiating a laser beam through a projection mask and controlling the size of the laser beam transmitted from the projection mask through an optical device that creates a projected image onto a polymer film. In partially removing the film forming material by laser etching, the projection mask is used to form at least two sheets of laser light transmitting portions that block unnecessary transmission light and form laser light into a quadrilateral. The laser light transmitting portion is formed by a partial mask, and the laser light transmitting portion is moved in a direction in which the laser light transmitting portion closes a partial mask forming a pair of opposing sides of the quadrilateral of the partial masks. In the state where the laser light is formed into a quadrilateral from the state in which the laser light is closed, the opening in the film surface is rectangular in the polymer film, and a concave portion having a triangular cross section is formed. There is provided a that slopes forming method.
[0008]
Further, according to the present invention, in the above-mentioned slope forming method, the projection mask for forming a laser beam transmitting portion for shaping the laser beam into a rectangle, and the partial mask to be moved forming the long side of the rectangle, Is moved in a direction parallel to the short side of the rectangle and at a speed of 1.1 to 150 times the partial mask on one side of the opposite side to the partial mask on the other side to close the laser light transmitting portion and etch. By performing laser etching at a rate of 0.01 to 5 μm / pulse, a cross-sectional shape having an optical path conversion slope having an inclination angle of 35 to 48 degrees with respect to the plane of the polymer film and an upright surface having a slope of less than 50 to 90 degrees is formed. An operation of forming a concave portion having a triangular shape and a rectangular opening in the polymer film surface is repeated to form a light emitting means in which a plurality of the concave portions are discontinuously distributed on one surface of the polymer film. There is provided a method for producing an optical film characterized and.
[0009]
Further, the present invention provides a method for forming a metal layer by electroforming on a surface on which light emitting means of an optical film manufactured by the above method is formed, and then separating the metal layer and the optical film to obtain a mold. The method for manufacturing a mold for forming an optical film, characterized in that the radiation-curable resin is brought into close contact with a surface having a convex portion capable of forming a light-emitting means in the mold for forming an optical film, and Forming a molded layer that reflects the shape, irradiating the molded layer with radiation, curing it, and then separating it from the mold, and the optical film produced by the above method is a liquid crystal. An object of the present invention is to provide a liquid crystal display device which is arranged on at least one side of a cell.
[0010]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the recessed part excellent in shape precision can be formed by obstruction of the laser beam transmission part through mask movement, and the surface accuracy (flatness or linearity) of a slope, such as gentle and steep, and the intersection of a slope. The light emitting means that excels in the sharpness (sharp sharpness) of the groove apex, which can disperse and distribute the concave portions of the fine structure with high positional accuracy, and efficiently converts the light in the horizontal direction into the optical path in the vertical direction. An optical film having the same can be obtained.
[0011]
Further, by using the above-mentioned optical film, the light incident from the side surface or the corner of the liquid crystal display panel is efficiently converted in the viewing direction to form a thin, light, bright, and easy-to-view liquid crystal display device. In particular, in a method in which a radiation-curable resin is molded into a predetermined shape through a mold formed by an electroforming method and cured, an optical film having a predetermined light emitting means can be obtained efficiently.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The slope forming method according to the present invention includes irradiating a laser beam through a projection mask, and irradiating the polymer film by controlling the size of the laser beam transmitted from the projection mask through an optical device that creates a projection image. While partially removing the polymer film forming material by laser etching, the projection mask is used to form a laser light transmitting portion that blocks unnecessary transmission light and shapes the laser light into a quadrilateral. The laser is formed through an operation of forming at least two partial masks and moving a partial mask forming a pair of opposing sides of the quadrilateral of the partial masks in a direction in which the laser light transmitting portion is closed. When the light transmitting part is closed from the state in which the laser beam is formed into a quadrilateral, a concave part having a rectangular opening in the film surface and a triangular cross section is formed in the polymer film. It is intended to.
[0013]
Examples of the steps of the method are shown in FIGS. 1 is a laser oscillator, 2 and 3 are partial masks that form a projection mask, 21 and 31 are apertures that form a laser light transmitting portion that shapes a laser beam into a quadrilateral, and 4 is an optical element that creates a projected image 41 of the laser beam. A lens 5 as a device is a polymer film to be irradiated with laser light, and 51 is a concave portion formed in the polymer film 5.
[0014]
2A and 3A are mask stages for fixing and holding the partial masks 2 and 3, and 6 is a work stage for fixing and holding the polymer film 5. The mask stages 2A, 3A and the work stage 6 in the illustrated example can be independently moved in X-axis, Y-axis, and Z-axis directions based on three-dimensional orthogonal coordinates via a driving source (not shown). The axis can be rotated about each of the axis, the Y axis, and the Z axis.
[0015]
Therefore, the position and the arrangement angle of the partial mask 2 can be controlled independently of the partial mask 3 and the polymer film 5 through the movement and / or the rotation of the mask stage 2A in the respective axial directions. Similarly, the partial mask 3 and the polymer film 5 can be independently controlled via the mask stage 3A.
[0016]
Further, the position and the arrangement angle of the polymer film 5 can be controlled independently of the partial mask 2 and the partial mask 3 through the movement and / or the rotation of the work stage 6 in each of the axial directions. The laser oscillator 1 and the optical device 4 can be independently moved and rotated in each of the axial directions, so that the position and the arrangement angle with respect to the mask stages 2A and 3A (partial masks 2 and 3) can be controlled. It has become.
[0017]
Further, in the illustrated example, after controlling the position and the arrangement angle of the laser oscillator 1 and the optical device 4 with respect to the projection mask (2, 3), the state is maintained as a fixed system when forming the concave portion. However, they can also be formed so as to be integrally movable or / and rotatable in conjunction with the mask stage 2A and / or the mask stage 3A if necessary.
[0018]
As described above, in the partial masks 2 and 3 arranged in a vertical positional relationship based on the irradiation direction of the laser light, the laser light based on the laser oscillator 1 first passes through the quadrangular opening 21 in the partial mask 2, A portion other than the opening blocks the transmission of the other laser light as unnecessary light, and projects the laser beam image onto the partial mask 3.
[0019]
Next, the laser light projected onto the partial mask 3 via the partial mask 2 is transmitted through the quadrangular opening 31 in the partial mask 3, and portions other than the opening make other laser light unnecessary light. The transmission is shielded, and the size of the laser beam image based on the transmitted light is controlled (reduced) via the lens 4 to irradiate the polymer film 5, and the polymer film forming material is etched by the laser light. Disappears and is removed.
[0020]
In the above case, as shown in FIG. 2, the partial mask 2 and the partial mask 3 are formed such that the openings 21 and 31 form a laser beam into a quadrilateral and the opposing sides of the quadrilateral for opening and closing the partial mask 2. And the partial mask 3 are arranged so as to share one side at a time to form a laser light transmitting portion, and the polymer film 5 is irradiated with laser light through the laser light transmitting portion for forming the laser light into a quadrilateral (A : Start), the partial mask 2 is moved to the right side in the figure via the mask stage 2A, and the partial mask 3 is moved to the left side in the figure via the mask stage 3A to close the laser beam transmitting portion (B: End). In FIG. 2, the control system of the laser beam image via the lens 4 is omitted.
[0021]
By operating the laser beam transmitting portion from the open (quadrilateral) state to the closed state via the partial masks 2 and 3, the material for forming the polymer film is continuously removed according to the moving distance of each partial mask. In that case, the etching is deeper as the irradiation time of the laser light is longer (the position where the integrated value of the laser light transmission amount is larger), and therefore, closer to the closed position of the laser light transmission portion, as shown in FIG. 2B. A recess (groove) 51 having a triangular cross section and a square opening in the polymer film surface is formed. Note that such triangles and squares do not have to be exact, and deformation based on manufacturing accuracy or the like is allowed.
[0022]
Accordingly, a plurality of partial masks are used to form a deformable laser light transmitting portion, such as a laser light transmitting portion formed through the openings 21 and 31 of the partial masks 2 and 3, and the laser light transmitting portion is formed. By controlling the laser beam image of the quadrilateral irradiating the polymer film through the mask, specifically, by closing the laser light transmitting portion through the partial mask forming a pair of opposing sides of the quadrilateral, the partial mask Continuously changing the integrated value of the amount of transmission of laser light in the closing movement direction of the wafer, and continuously changing the etching amount per unit area in the depth direction of the formed recess, thereby forming a slope in the recess. be able to.
[0023]
In the above example, each partial mask is formed by one mask, but a combination of two or more masks can be used as a partial mask to form a desired form. Further, in the illustrated example, a laser beam transmitting portion for forming a laser beam into a quadrilateral is formed as an arrangement relationship in which the quadrangular openings provided in the partial masks 2 and 3 are vertically overlapped, but the laser beam transmitting portion is a projection mask. It is sufficient that an opening form for forming a laser beam into a quadrilateral is formed through the entirety of two or three or more partial masks forming the above.
[0024]
Therefore, a projection mask is formed by using, for example, four partial masks of a total shielding type formed of strips or the like having no opening, and these are arranged in the shape of a square so that a quadrangular opening is formed in the center. It is also possible to form a laser light transmitting portion for forming the laser light into a quadrilateral. In addition, a projection mask is formed by using two pieces of a cono-shaped or L-shaped totally shielded partial mask, or two pieces of a cono-shaped and an I-shaped fully shielded partial mask, and a quadrilateral opening is formed at the center thereof. It is also possible to form a laser light transmitting portion for forming the laser light into a quadrilateral by arranging the laser light in a shape of a square.
[0025]
As described above, the projection mask can be formed as a combination of a plurality of partial masks having an appropriate form, which can form a laser light transmitting portion for forming a laser beam into a quadrilateral. There is no particular limitation on the size of the quadrilateral of the laser light transmitting portion formed via the projection mask. By controlling the size of the laser light transmission image by the laser light transmission unit via an optical device such as a lens, and generally shrinking and irradiating the polymer film, the size control in the process is also possible. Therefore, the size of the quadrilateral can be appropriately determined according to the size of the concave portion to be formed.
[0026]
Further, the shape of the quadrilateral in the laser beam transmitting portion is also arbitrary, and the size of the concave portion formed on the polymer film and the shape of the inclined surface through the rectangular shape are also arbitrary. The angle of the slope of the concave portion to be formed can be controlled by the moving speed of the partial mask when closing the quadrilateral of the laser beam transmitting portion, the intensity and amount of the laser beam to be irradiated, and the like. By making the irradiation amount of the laser beam constant, making the etching amount per unit time constant, and moving the partial mask at a constant speed, it is possible to form a slope with a constant inclination angle.
[0027]
Therefore, the inclination angle of the formed slope can be changed by changing the speed at the time of the closing movement of the partial mask, and when the irradiation amount of the laser beam is constant, the slope becomes smaller as the movement speed increases. Can be formed. In addition, the laser beam irradiation may be stopped or interrupted during the closing movement of the partial mask, so that a horizontal plane follows the slope or a horizontal plane intervenes between the slopes. Further, when the partial masks are closed and moved, the speeds of the plurality of partial masks to be moved can be made the same to form slopes having the same inclination angle, and slopes having different inclination angles can be formed at different speeds.
[0028]
The above-described slope forming method can be preferably applied to the formation of the light emitting means in which the concave portions are distributed and distributed. That is, for example, in the illustrated example, the forming material at a predetermined position of the polymer film is partially removed by repeating the above-described etching operation for forming the concave portion due to the movement of the polymer film 5 through the work stage 6 and the intermittent laser irradiation. The light emitting means can be formed by dispersing and dispersing a plurality of concave portions. In such a case, for example, by randomly moving the polymer film 5 through the works stage, or by giving a difference in length to the moving distance, the concave portions are randomly arranged, and the light in a state where the distribution density changes further. The emission means can be easily formed.
[0029]
As illustrated in FIG. 5A, the optical film that can be preferably used in the liquid crystal display device and the like includes an optical path conversion slope a having an inclination angle θ1 of 35 to 48 degrees with respect to a plane formed by the polymer film 5 and an inclination angle θ2 of the inclination angle θ2. A plurality of concave portions 51 having a triangular cross-sectional shape having an elevation surface b of less than 50 to 90 degrees and a rectangular opening in the polymer film surface are discontinuously distributed on one surface of the polymer film. It has light emitting means.
[0030]
For example, in the above-described slope forming method, the formation of the concave portion may be performed by forming a laser light transmitting shape through a projection mask into a rectangular shape of a laser beam, and moving the partial mask to close the laser light transmitting portion. Along with the partial masks forming a pair of long sides of the rectangle, the partial masks on the opposite sides are moved in a direction parallel to the short sides of the rectangle to close the laser light transmitting portion, and when closing the laser light transmitting portion, The partial mask on one side of the opposite side is moved at a speed 1.1 to 150 times that of the partial mask on the other side, and laser etching is performed at an etching rate (etching amount per shot) of 0.01 to 5 μm / pulse. It can be performed by a method or the like.
[0031]
That is, through a projection mask formed of at least two partial masks forming a laser light transmitting portion for shaping a laser light into a rectangle by blocking unnecessary transmitted light, 0.01 to 5 μm per pulse. Irradiating a laser beam having a strength capable of etching a polymer film having a thickness of 0.05 to 4 μm, particularly 0.1 to 2 μm, and transmitting the laser beam transmitted from the projection mask through an optical device for producing a projection image. While irradiating the polymer film by controlling (reducing) the size of the laser light transmission image, the partial mask forming the pair of long sides of the rectangle among the partial masks is placed on one side / other side thereof. An operation of moving the laser light transmitting portion in a direction parallel to the short side of the rectangle and in a direction in which the laser light transmitting portion is closed at a speed ratio of 1.1 to 150, particularly 1.5 to 100, particularly 2 to 70. Through the laser When the transmitting portion is closed from a state where the laser beam is formed into a predetermined rectangular shape, and the forming material of the polymer film is partially removed by laser etching, the inclination angle with respect to the polymer film plane is 35 to 48 degrees. A cross section having an optical path changing slope and an elevation of less than 50 to 90 degrees has a triangular cross section, and a recess having a rectangular opening at the polymer film surface can be formed.
[0032]
In addition, the optical film is obtained by repeatedly applying the above-described concave portion forming method to different positions on the polymer film and distributing a plurality of the concave portions discontinuously on one surface of the polymer film to form light emitting means. be able to. Note that the rectangle and the parallel movement need not be strict, and deformation based on manufacturing accuracy or the like is allowed.
[0033]
In the above, as the laser oscillator, for example, an excimer laser, a YAG laser, a CO ₂ One or more suitable lasers or femtosecond lasers may be used. Ablation processing using an oscillator that can obtain laser light in the ultraviolet region having a wavelength of 400 nm or less is particularly preferable from the viewpoint of the precision of fine processing. The shape and size of the recesses to be formed and the arrangement of the dispersion distribution depend on the resolution and positioning accuracy of the laser processing machine with optical equipment, etc., and the accuracy of the formed slope is also the oscillation frequency of the laser processing machine, the stage, etc. It is preferable to use a high-precision processing machine, because it depends on the speed and accuracy of the movement via the.
[0034]
As the partial mask for forming the projection mask, an appropriate mask made of an ultraviolet shielding material such as a metal can be used. A glass mask formed by depositing a suitable ultraviolet shielding material such as a metal or a dielectric on a glass plate made of quartz or the like and patterning the deposited layer as necessary to form a laser light transmitting portion can also be used. .
[0035]
The deposition material for the glass mask is not limited, but chromium, aluminum, molybdenum, a dielectric multilayer film, or the like is preferable from the viewpoint of durability against laser light and resolution. Note that the partial mask may be formed of two or three or more masks as described above, and the masks may be overlapped and provided for laser light irradiation.
[0036]
When forming the light emitting means by distributing a plurality of concave portions as described above, the polymer film is moved. In this case, both the polymer mask and the projection mask or the partial mask forming the same are synchronized. It is also possible to adopt a method of moving by moving.
[0037]
As the polymer film, a film made of an appropriate material that exhibits electrical insulation and can be etched by laser light can be used, and is not particularly limited. Generally, a polymer film is used. Above all, from the viewpoint of workability with ultraviolet laser light, an ultraviolet-absorbing resin such as an acrylic, methacrylic or urethane-based ultraviolet curable resin is preferred. Further, those having excellent transmittance in the visible light region are preferable.
[0038]
By the way, examples of the polymer film include polyester resins, epoxy resins, urethane resins and polystyrene resins, polyethylene resins and polyamide resins, polyimide resins and ABS resins, acrylic resins and cellulose resins, and polycarbonates. Coating films and films made of resin, silicone resin, norbornene resin, and the like.
[0039]
Further, polymers described in JP-A-2001-343529 (WO 01/37007), for example, (A) a thermoplastic resin having a substituted or / and unsubstituted imide group in a side chain, and (B) a substituted or / or substituted side chain in a side chain. And a polymer film such as a coating film or film made of a resin composition containing A and B with a thermoplastic resin having an unsubstituted phenyl group and a nitrile group.
[0040]
Incidentally, a specific example of the above-mentioned resin composition includes a resin composition containing an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile-styrene copolymer. The film can be formed by extrusion molding of a resin composition or the like.
[0041]
A polymer film that is preferable in terms of heat resistance, chemical resistance, and laser processability is a polymer film made of a thermosetting resin, particularly, a polyimide resin. Although the thickness of the polymer film is arbitrary, it is preferably 500 μm or less, and particularly preferably 10 to 200 μm, from the viewpoints of handleability at the time of processing, sharpness of an edge portion in a formed concave portion, and flatness of a processed surface. The polymer film can be placed on a work stage while being held on a glass substrate or a metal plate as needed.
[0042]
The optical film can be manufactured integrally by the above-described method. A preferable method for producing an optical film from the viewpoint of mass productivity is to produce a mold for forming an optical film using the optical film obtained by the above method as a matrix, and mass-produce the optical film using the mold. How to
[0043]
The method is, for example, after forming a metal layer by electroforming on the surface of the optical film serving as a matrix on which the light emitting means is formed, separating the metal layer and the optical film to form a mold for forming an optical film. The mold is manufactured, and a radiation-curable resin is adhered to a surface of the mold having a convex portion capable of forming the light emitting means, and a molding layer that reflects the shape of the light emitting means is formed. After irradiation and curing, it can be carried out by a method of separating the manufactured optical film from a mold or the like.
[0044]
FIG. 5 shows an example of steps of the method. The figure shows the steps from the formation of the mold (A to C) to the formation of the optical film (D, E). As shown in the figure, the optical film 8 is provided with a plurality of concave portions having an optical path changing slope a having an inclination angle θ1 of 35 to 48 degrees with respect to the film surface via a mold 7 having a predetermined convex portion 71. Is formed by molding.
[0045]
The mold 7 is formed by applying an electroforming method to a polymer film (optical film) 5 provided with a plurality of light emitting means having predetermined concave portions 51 as in the example of FIG. 5B. Thus, as shown in the example of FIG. 5C, the mold 7 having the convex portions 71 corresponding to the concave portions 51 provided in the polymer film 5 with high precision can be formed.
[0046]
As the above-mentioned electroforming method, a metal is filled on a side provided with the concave portion of the polymer film, and a metal mold having a replica having a replica of a surface shape of the side provided with the concave portion of the polymer film is used. A method according to the related art can be applied. Therefore, when forming the metal layer, a conductive film is provided on the side of the polymer film on which the concave portion is provided, and a method according to the related art can be applied to the formation of the conductive film.
[0047]
There is no particular limitation on the type of metal forming the mold, and in general, for example, gold, silver, copper, iron, nickel, cobalt, or alloys thereof are used, and nitrides, phosphorus, and the like are added. It may be. The kind of metal to be used may be one kind or two or more kinds, and a mold formed by laminating different kinds of metals can also be formed.
[0048]
The thickness of the metal layer formed as a mold may be appropriately determined. A metal foil or a metal plate made of a metal layer having a thickness of about 0.02 to 3 mm at a portion having no convex portion from the viewpoint of prevention of breakage at the time of separation from the polymer film and handling properties at the time of forming an optical film. Is preferably used.
[0049]
The optical film 8 is formed by, for example, applying a radiation-curable resin to a transparent film or the like as needed and supporting the same, as shown in FIG. The radiation-curable resin layer transfers the surface shape of the mold on the side where the projections are formed, thereby forming a molding layer that reflects the surface shape, and irradiating the radiation to cure the molding layer. 8 is separated from the mold 7.
[0050]
As described above, as shown in FIG. 5E, the concave portion 81 and the surface shape corresponding to the surface shape on the convex portion forming side of the mold with high precision are provided. And an upright surface b having an inclination angle θ1 of 35 to 48 degrees with respect to the film surface, and an upright surface b having an inclination angle θ2 of less than 50 to 90 degrees. An optical film 8 having a light emitting means in which a plurality of concave portions 81 having a rectangular opening are discontinuously distributed on one surface is obtained.
[0051]
In the above, a preferred method of manufacturing an optical film is to wind a deformable mold around the outer periphery of a cylindrical or cylindrical circular rotating body, and rotate the mold through the rotating body while rotating the mold. A radiation-curable resin coating layer provided on a long transparent film is sequentially pressed to form a molding layer that reflects the surface shape of the mold, and the molding layer is irradiated with radiation through the transparent film. Then, the optical film is manufactured continuously.
[0052]
The optical film 5 (8) according to the method of the present invention has an optical path conversion slope having an inclination angle of 35 to 48 degrees with respect to a plane formed by the polymer film 5 or the film (8) as shown in the examples of FIGS. A plurality of concave portions 51 (81) having a triangular cross-sectional shape, a rectangular opening in the polymer film surface or the film surface, and a discontinuous distribution on one surface. It has emission means. The light emitting means continuously changes the integrated value of the amount of transmitted laser light with good linearity up to the top of the forming groove because the inclined surface of the concave portion is based on the closing operation of the laser light transmitting portion of the partial mask as described above. It has excellent sharpness at the top of the groove and excellent linearity (flatness) of the slope including the upright surface, and has a small-sized concave portion cut at both ends in the long side direction at acute angles, so that the optical path conversion slope is reflected. The efficiency is excellent and the reflected light is excellent in directivity.
[0053]
Therefore, the optical film reflects the light incident from the side surface or the corner of the liquid crystal cell through the light source or the transmitted light through the optical path changing slope to the rear surface side (the side having no light emitting means), and thus the liquid crystal display. The optical path is changed in the viewing direction of the panel and emitted, and the emitted light can be used as illumination light (display light) for a liquid crystal display panel or the like. In that case, the optical film is generally arranged such that the surface on which the light emitting means is formed is on the outside in the direction along the plane of the liquid crystal cell.
[0054]
In the above, a transparent film that may form an optical film is used as a support for the radiation-curable resin, if necessary, of an appropriate material that exhibits transparency according to the wavelength range of light incident via a light source or the like. It can be formed using one kind or two or more kinds. Incidentally, in the visible light region, for example, a transparent resin represented by the above-mentioned polymer film, a curable resin which can be polymerized by heat, ultraviolet rays, electron beams, and the like are exemplified.
[0055]
From the standpoint of increasing the efficiency of incidence on the light path conversion slope to obtain a liquid crystal display device that is bright and has excellent display uniformity, the transparent film preferably has a refractive index equal to or higher than that of a liquid crystal cell, particularly, its cell substrate, and especially 1 .49 or more, especially 1.52 or more. From the viewpoint of suppressing surface reflection in the case of a front light system, the refractive index is preferably 1.6 or less, more preferably 1.56 or less, and particularly preferably 1.54 or less. In addition, such a refractive index is generally based on the D line in the case of the visible light range, but is not limited to the above when there is specificity or the like in the wavelength range of the incident light, and depends on the wavelength range. (The same applies hereinafter).
[0056]
A transparent film that is preferable from the viewpoint of suppressing a luminance unevenness and a color unevenness and obtaining a liquid crystal display device with a small display unevenness does not exhibit birefringence or has a small birefringence, and particularly, an average in-plane retardation of 50 nm. These are: When a transparent film having a small retardation is used, when linearly polarized light is incident through an optical film or the like, the polarization state can be favorably maintained, which is advantageous for preventing a deterioration in display quality.
[0057]
From the viewpoint of preventing display unevenness, the in-plane preferable average retardation of the transparent film is 30 nm or less, particularly 20 nm or less, and particularly 10 nm or less, and the dispersion of the retardation at each location is as small as possible. preferable. Further, a transparent film made of a material having a small photoelastic coefficient is preferable from the viewpoint of suppressing the internal stress generated in the transparent film and preventing the occurrence of a phase difference due to the internal stress. In addition, the average retardation in the thickness direction of the transparent film is preferably 50 nm or less, more preferably 30 nm or less, and particularly preferably 20 nm or less from the viewpoint of preventing display unevenness and the like.
[0058]
Such a low-retardation transparent film can be formed by an appropriate method such as a method of removing an internal optical distortion by a method of annealing an existing film or the like. A preferred forming method is a method of forming a transparent film having a small retardation by a casting method. The retardation in the transparent film is preferably based on light in the visible region, particularly light having a wavelength of 550 nm.
[0059]
The above-mentioned average phase difference in the plane is defined by (nx−ny) × d, and the average phase difference in the thickness direction is defined by {(nx + ny) / 2−nz} × d. Where nx is the average refractive index in the direction showing the maximum refractive index in the film plane, ny is the average refractive index in the direction orthogonal to the nx direction in the film plane, and nz is the average refractive index in the thickness direction of the film. , D means the average thickness of the film.
[0060]
The transparent film is usually formed as a single layer, but may be formed as a laminate made of the same or different materials. The thickness of the transparent film can be appropriately determined and is not particularly limited. However, the thickness is preferably 5 to 500 μm, more preferably 10 to 300 μm, and particularly preferably 20 to 100 μm from the viewpoint of reducing the thickness and weight. With such a thickness, sizing by punching or the like can be easily performed.
[0061]
The light emitting means provided on the optical film includes an optical path changing slope having an inclination angle of 35 to 48 degrees with respect to a plane formed by the polymer film 5 or the film 8 as shown in FIGS. A plurality of concave portions 51 and 81 having a rectangular cross-sectional shape, a rectangular opening in the polymer film surface or the film surface, and a discontinuous distribution on one surface; Is formed as
[0062]
The recess having a triangular cross section is advantageous from the viewpoint of reduction in visibility due to size reduction, manufacturing efficiency, and the like. The recess means being recessed (groove) in the polymer film or the optical film. The cross section means a cross section of the concave portion with respect to the optical path conversion slope. Note that the triangle based on the cross section is not strictly meaning as described above, and a change in the angle of the surface and a roundness based on the processing accuracy at the corner (groove apex) formed by the intersection of the surfaces are allowed, but in the present invention, Its processing accuracy is excellent.
[0063]
As described above, the incident light or the transmitted light from the side direction by the light source disposed on the side surface or the like of the liquid crystal cell is optically path-converted to the rear surface side of the optical film having no light emitting means through the optical path conversion slope a, and Light having excellent directivity in the normal direction with respect to the light source and the like can be emitted with high utilization efficiency of the light source light.
[0064]
If the inclination angle of the optical path conversion slope is less than 35 degrees, the angle of the display light emitted from the liquid crystal display panel exceeds 30 degrees, which is disadvantageous for visual recognition. On the other hand, when the inclination angle of the optical path conversion slope exceeds 48 degrees, light is likely to leak from the slope without being totally reflected, and the light use efficiency is reduced.
[0065]
In the above, in place of the reflection method by the optical path conversion slope, when the scattering reflection method by the light emitting means having a roughened surface, it is difficult to reflect in the vertical direction and in the direction inclined more greatly than the front direction from the liquid crystal display panel. The light is emitted and the liquid crystal display becomes dark and the contrast becomes poor.
[0066]
Efficient total reflection through the light path conversion slope, emits light with good directivity in the direction normal to the polymer film surface or film surface from the side having no light emitting means, illuminates the liquid crystal cell efficiently and is bright and easy to see From the viewpoint of achieving a liquid crystal display, the preferable inclination angle θ1 of the optical path conversion slope is 38 to 45 degrees, particularly 40 to 43 degrees.
[0067]
The light emitting means is formed by dispersing and distributing a plurality of discontinuously interrupted concave portions as in the examples of FIGS. The concave portions may be distributed in parallel based on the optical path changing slope as in the example of FIG. 3 or may be irregularly distributed. Furthermore, as shown in the example of FIG. 4, the distribution may be arranged in a pit shape (concentric shape) with respect to the virtual center.
[0068]
Incidentally, the distribution of the pit-like arrangement described above, when irradiating a laser beam, assuming a virtual center on the end face or outside of the polymer film, and a portion in a direction orthogonal to virtual radiation derived from the virtual center. It can be formed by providing a concave portion so as to form a laser light transmitting portion closing line of the mask. In addition, assuming two or more virtual centers, the light emitting means may be formed of a plurality of concave portions distributed and arranged in a pit shape with respect to each virtual center.
[0069]
The arrangement state of the plurality of concave portions based on the dispersion distribution can be appropriately determined according to the form of the concave portions. As described above, the light path conversion slope a reflects the incident light from the side surface of the light source from the side direction toward the back side in the illumination mode and converts the light path, so that all the light rays pass through the concave portion having the light path conversion slope. Dispersing and dispersing discontinuously on one surface of the optical film so that the ratio is 75 to 92% and the haze is 4 to 20% is to change the optical path of the light from the side direction via the light source to form the liquid crystal cell. It is preferable from the viewpoint that a surface light source to be efficiently illuminated is obtained and a liquid crystal display which is bright and has excellent contrast is achieved.
[0070]
Such characteristics of the total light transmittance and the haze can be achieved by controlling the size and distribution density of the concave portions. For example, the area occupied by the projected area of the light emitting means in the optical film on the surface where the light emitting means is formed is reduced by one. / 100 to 1/8, preferably 1/50 to 1/10, particularly 1/30 to 1/15.
[0071]
More specifically, if the size of the concave portion or the optical path conversion slope is large, the existence of the slope is easily recognized by the observer, and the display quality is greatly reduced, and the uniformity of illumination with respect to the liquid crystal cell is also reduced. Considering that the opening becomes easier, the opening on the surface of the polymer film is a recess having a rectangular shape, and the long side of the opening is at least three times the short side length, particularly 5 or more, especially 8 or more. Is preferred.
[0072]
Further, it is preferable that the length of the optical path conversion slope is not less than 5 times the depth of the recess, more preferably not less than 8 and especially not less than 10. Further, it is preferable that the length of the optical path conversion slope is 500 μm or less, particularly 200 μm or less, particularly 10 to 150 μm, and the depth and width of the concave portion are 2 μm to 100 μm, particularly 5 to 80 μm, particularly 10 to 50 μm. Note that the length is based on the long side length of the optical path conversion slope, and the depth is based on the light emitting unit forming surface of the optical film. The width is based on the length in a direction orthogonal to the long side direction and the depth direction of the optical path conversion slope.
[0073]
The surface that forms the concave portion and does not satisfy the optical path conversion slope a having a predetermined inclination angle, that is, the upright surface b that faces the optical path conversion slope a contributes to emitting the incident light from the cell side direction from the back surface. It is preferable not to affect display quality and light transmission or light emission as much as possible. By the way, if the inclination angle θ2 of the vertical surface is small, the projected area with respect to the film surface becomes large, and in the external light mode by the front light method in which the optical film is arranged on the viewing side, the surface reflected light by the vertical surface returns to the observation direction and is displayed. It is easy to impair the quality.
[0074]
Therefore, the larger the inclination angle θ2 of the upright surface is, the more advantageous it is. As a result, the projected area with respect to the film surface can be reduced, and the decrease in the total light transmittance can be suppressed. The reflected light on the surface can be reduced, and the reflected light can be inclined in the direction of the film surface, so that the influence on the liquid crystal display can be suppressed. From such a point, the preferable inclination angle θ2 of the upright surface is 60 degrees or more, particularly 70 degrees or more, and particularly 75 to less than 90 degrees.
[0075]
The slope forming the concave portion 51 (81) is preferably a straight surface. Further, the cross-sectional shape of the concave portion may be such that the inclination angle or the like is constant over the entire surface of the sheet, or the uniformity of light emission on the optical film may be taken into account by absorbing loss or attenuation of transmitted light due to optical path conversion. For the purpose of realization, the concave portion may be made larger as the distance from the side surface on which light is incident increases.
[0076]
Further, the light emitting means may be a light emitting means in which the concave portions are distributed and distributed at a constant pitch, or the light emitting means may have a narrower pitch as the distance from the side surface on which light is incident is increased, thereby increasing the distribution density of the concave portions. You can also. Furthermore, uniform light emission on the optical film can be achieved by a light emitting means with a random pitch in which the distribution density and arrangement position of the concave portions are irregular. The random pitch is particularly advantageous for preventing moire due to interference with pixels. Therefore, the light emitting means may be composed of a combination of concave portions having different shapes and the like in addition to the pitch.
[0077]
It is preferable that the optical path changing slope in the concave portion faces the direction of light to be incident from the side surface direction of the liquid crystal cell from the viewpoint of improving the emission efficiency. Therefore, when the linear light source is used, the optical path conversion slope is preferably oriented in a certain direction. In addition, when a point light source such as a light emitting diode is used, it is preferable that the optical path conversion slope faces the direction of the light emission center of the point light source.
[0078]
There is no particular limitation on the shape of the intermittent end of the concave portion, but it is preferable that the concave portion is dug at an acute angle from the viewpoint of suppressing the effect of reducing the incident light on that portion. The angle is preferably 60 to 90 degrees according to the plane.
[0079]
In addition, the optical film has a flat surface whose front and back surfaces are as smooth as possible, except for a concave portion forming the light emitting means, and more particularly, a flat surface having an angle change of ± 2 ° or less, particularly 0 °. Is preferred. It is preferable that the angle change is within 1 degree per 5 mm in length. By making such a flat surface, most of the film surface can be made a smooth surface with an angle change of 2 degrees or less, and the light transmitted inside the liquid crystal cell can be used efficiently, and a uniform image that does not disturb the image can be obtained. Light emission can be achieved.
[0080]
As described above, the pit-like arrangement of the concave portions is such that a point-like light source is arranged on a side surface of a liquid crystal display panel or the like, and the radial incident light or the transmission light from the side direction by the point-like light source is transmitted through the optical path conversion slope a. It is an object of the present invention to make the optical film emit light as uniformly as possible by converting the light, and to emit light having excellent directivity in the normal direction to the liquid crystal cell or the like from the optical film with efficient use of the light source light.
[0081]
Therefore, it is preferable to perform the pit-like arrangement of the concave portions so that a virtual center is formed on the end face of the optical film or outside thereof so that the point light source can be easily arranged. The virtual center can be formed at one location or at two or more locations with respect to the same or different optical film end faces.
[0082]
In the above, when forming the molded cured layer of the radiation-curable resin, when using a transparent film for support, the optical film can be obtained as a transparent film and the molded cured layer is fixedly integrated, It can also be obtained as being composed of the cured molding layer in a state separated from the transparent film. Separation of the transparent film and the cured molding layer can be achieved by an appropriate method such as a method of treating the transparent film with a release agent.
[0083]
The radiation-curable resin forming the molded cured layer is, for example, one of appropriate resins which can be cured by irradiation with ultraviolet rays such as the above-described ultraviolet-curable resins, particularly, irradiation with ultraviolet rays and / or electron beams. Alternatively, two or more types can be used, and the type is not particularly limited. Above all, a radiation-curable resin capable of forming a molded cured layer having excellent light transmittance is preferable.
[0084]
In the case of the above-mentioned fixing and integration, if the difference in the refractive index between the molded cured layer and the transparent film is large, the light emission efficiency may be greatly reduced due to interface reflection or the like. From the viewpoint of preventing this, a radiation curable resin capable of forming a molded cured layer having a refractive index difference as small as possible from the transparent film, preferably within 0.10, particularly preferably within 0.05 is preferred.
[0085]
Further, in the above case, it is preferable from the viewpoint of emission efficiency that the refractive index of the molded cured layer to be added is higher than that of the transparent film. The thickness of the coating layer of the radiation-curable resin formed on the transparent film is 1 to 5 times, preferably 1.1 to 3 times, particularly 1.2 to 2 times the height of the convex portion in the mold. Preferred, but not limited to.
[0086]
The optical film according to the present invention is configured such that, through the light emitting means (optical path changing slope), the optical path is changed in the direction (normal direction) in which the incident light from the side direction by the light source or the transmitted light is excellent in verticality advantageous for visual recognition (normal direction). As a result, the light can be efficiently emitted and exhibit good transparency to external light. Various devices such as a liquid crystal display device of a type can be formed.
[0087]
The liquid crystal display device can be formed by, for example, a method in which an optical film is arranged on at least one side of a liquid crystal cell such that the side having the light emitting means is on the outside. In that case, one or more light sources may be provided on one or more side surfaces or corners of the liquid crystal cell, particularly on one or more side surfaces or corners of the cell substrate on which the optical film is disposed. Can be formed. The optical film is preferably bonded to a liquid crystal cell or the like via an adhesive layer from the viewpoint of achieving a bright display.
[0088]
When forming the illumination mechanism, in the case of an optical film having light emitting means in a pit-like arrangement, the light in the pit-like arrangement is used because a bright display is achieved by efficiently using radial incident light from a point-like light source. It is preferable to dispose a point light source on the side surface of the liquid crystal cell on a vertical line including the virtual center of the emission unit. In such an arrangement of the point light source corresponding to the virtual center, the side on which the point light source is arranged of the cell substrate is protruded depending on whether the virtual center of the light emitting means is at the end face of the optical film or outside thereof. Appropriate countermeasures such as the method can be adopted.
[0089]
As a light source arranged on the side surface of the liquid crystal cell, an appropriate light source can be used. For example, in addition to the above-mentioned point light sources such as light-emitting diodes, linear light sources such as (cold and hot) cathode tubes, arrays of point light sources arranged in a line or a plane, or point light sources and linear conductors A combination of light plates for converting incident light from a point light source into a linear light source via a linear light guide plate can be preferably used.
[0090]
The light source is preferably arranged on the side of the cell where the optical path conversion slope of the optical film faces, from the viewpoint of emission efficiency. By arranging the optical path conversion slope so as to face the light source as perpendicularly as possible, including the case of the above-mentioned pit-like arrangement, efficiently convert incident light from the side surface through the light source into a surface light source. Light can be emitted with high efficiency. In the case of a pit-like arrangement, a point light source can be arranged at one or more places corresponding to the virtual center of the light emitting means on the optical film.
[0091]
The light source enables visual recognition in an illumination mode by lighting the light source, and in the case of a liquid crystal display device for both external light and illumination, there is no need to light when viewing in the external light mode using external light. It can be switched on and off. An arbitrary method can be adopted as the switching method, and any of the conventional methods can be adopted. Note that the light source may be of a different color emission type capable of switching emission colors, or may be of a type capable of emitting different colors through different types of light sources.
[0092]
If necessary, the light source may be a combination body in which appropriate auxiliary means such as a reflector surrounding the liquid crystal cell are arranged to guide the divergent light to the side surface. As the reflector, a suitable reflection sheet such as a resin sheet provided with a metal thin film having a high reflectance, a white sheet, or a metal foil can be used. The reflector can also be used as a fixing means that also serves as a surrounding of the light source by a method in which the end is bonded to an end of a cell substrate or the like.
[0093]
In general, a liquid crystal display device is configured by appropriately assembling components such as a liquid crystal cell functioning as a liquid crystal shutter, a driving device associated therewith, a front light or a backlight, and a reflective layer and a compensating retardation plate as necessary. It is formed. In the present invention, there is no particular limitation except that an illumination mechanism is formed using the above-described optical film and light source, and the light-emitting device can be formed according to a conventional front light type or backlight type.
[0094]
Therefore, the liquid crystal cell to be used is not particularly limited, and an appropriate reflection type or transmission type in which liquid crystal is sealed between cell substrates through a sealing material and display light is obtained through light control by the liquid crystal or the like. Can be used.
[0095]
Incidentally, specific examples of the above-mentioned liquid crystal cell include twisted and non-twisted types such as TN type liquid crystal cell, STN type liquid crystal cell, IPS type liquid crystal cell, HAN type liquid crystal cell, OCB type liquid crystal cell and VA type liquid crystal cell, and guest type. A liquid crystal cell of a host system or a ferroelectric liquid crystal system, or a liquid crystal cell of a light diffusion type such as an internal diffusion type is exemplified. The liquid crystal driving system may be an appropriate one such as an active matrix system or a passive matrix system.
[0096]
The arrangement of a reflective layer is indispensable in a front-light type reflective liquid crystal display device, but the position of the reflective layer can be provided inside the liquid crystal cell also as an electrode, or provided outside the liquid crystal cell. You can also.
[0097]
For the reflective layer, for example, a coating layer containing a powder of a high-reflectance metal such as aluminum, silver, gold, copper, or chromium in a binder resin, an additional layer of a metal thin film formed by a vapor deposition method, or the like, The reflecting layer can be formed as a suitable reflecting layer such as a reflecting sheet, a metal foil, a transparent conductive film, or a dielectric multilayer film in which an additional layer is supported by a base material. When a transmissive liquid crystal display device is used for both external light and illumination, the reflective layer disposed outside the optical film can be appropriately formed in accordance with the above.
[0098]
On the other hand, a transmission type liquid crystal display device can be formed by arranging an optical film as a component of a backlight on the viewing back side of a liquid crystal cell. In this case, by providing a reflective layer on the back side (outside) of the light emitting means, light leaking from an optical path changing slope or the like is reflected and returned to the direction of the liquid crystal cell, so that it can be used for cell illumination and luminance is improved. be able to.
[0099]
In the above case, by using the reflection layer as a diffuse reflection surface, the reflected light can be diffused and directed in the front direction, and can be directed in a more effective direction by visual recognition. In addition, by providing the above-mentioned reflective layer, it can be used as a transmissive liquid crystal display device of both external light and illumination type as described above.
[0100]
【Example】
Example 1
Two types of partial masks each having a rectangular opening of 1500 μm in length, 200 μm in width or 2000 μm in length, and 300 μm in metal foil are arranged above and below, and a laser light transmitting portion having a length of 1500 μm and a width of 150 μm is obtained by overlapping the openings. A projection mask to be formed is formed, and an excimer laser beam having a wavelength of 248 nm is irradiated with a beam width of 1.5 mm through the mask, and the transmitted light of the projection mask is reduced to 1/15 through a lens to obtain a thickness. In the method of irradiating a 50 μm polyimide film, the two partial masks are irradiated with a laser beam at an etching rate of 0.26 μm / pulse and the two partial masks are opened at a speed ratio of 30: 7 from an open state with a width of 150 μm. It was moved at a constant speed in the width direction at different speeds to make it a closed state, and a recess was formed (FIGS. 1, 2).
[0101]
The concave section had a triangular cross section, and the deepest etched portion (groove apex) corresponded to the closing line of the laser light transmitting section. The recess has a length of about 100 μm, a width of about 10 μm, and a depth of about 8 μm, and has an optical path conversion slope having an inclination angle of about 42 degrees with respect to the film surface and an upright surface having an inclination angle of about 75 degrees with respect to the slope. (FIG. 2B), the groove apex of the concave portion was sharp and both ends were dug at an acute angle, and the vertical surface as well as the optical path conversion slope had excellent surface accuracy (flatness).
[0102]
Next, the etching process described above is repeated while scanning each axis of XYZθ of the work stage and changing the position with respect to the polyimide film, and a plurality of the concave portions are randomly distributed on one surface of the polyimide film, and the distribution density is equal to or smaller than the film density. A polymer film (an optical film as a matrix) having a size larger as the distance from one side was increased (FIGS. 4 and 5A). The area occupied by the opening of the recess on the film surface was 1/10.
[0103]
Next, nickel is filled into the concave surface of the polymer film by an electroforming method to form a metal layer having a thickness of about 200 μm, and then the polymer film is peeled to have a predetermined convex portion forming surface. A mold was obtained (FIGS. 5B and C). Then, a radiation-curable acrylic resin is applied in a thickness of 75 μm on the convex portion forming surface of the mold, and a transparent film is put thereon, and excess resin and air bubbles are extruded to form a surface shape of the mold. After forming a molded layer, the molded layer is cured by irradiating it with radiation, and the formed cured layer is peeled from the mold to obtain an optical film having light emitting means (FIG. 5D, E).
[0104]
The light emitting means in the optical film has an optical path conversion slope having an inclination angle of about 42 degrees with respect to the film surface, and an upright surface having an inclination angle of about 75 degrees facing the slope, and has a length of about 100 μm, a width of about 10 μm, and a depth of about 10 μm. It consisted of a plurality of recesses having a thickness of about 8 μm, which corresponded to the light emitting means comprising the recesses provided in the matrix polyimide film with high precision. Therefore, the groove apex of the concave portion is sharp and both ends are dug at an acute angle, and the vertical surface as well as the optical path changing slope has excellent surface accuracy.
[0105]
Comparative example
A light guide plate having light emitting means formed of stripe-shaped concave portions formed by machining was used.
[0106]
Evaluation test
A liquid crystal display device incorporating the optical film according to the example or the light guide plate according to the comparative example was formed. As a result, occurrence of moire was confirmed in the comparative example. In addition, interface reflection occurred in the gap between the light guide plate and the panel, and the contrast was reduced, and defects in the light guide plate were very conspicuous when the light guide plate was viewed directly. Further, the laser etching process by the conventional method has reduced the flatness of the slopes of the stripe-shaped concave portions, particularly the flatness of the vertical surfaces, and the roundness of the groove apex is large, so that the visibility and luminance of the liquid crystal panel are reduced.
[0107]
On the other hand, in the above embodiment, since the light emitting means is formed by randomly arranging minute-sized concave portions excellent in the surface accuracy of the inclined surface including the upright surface and the sharpness of the groove apex, no moiré is generated, and the panel is not generated. Interfacial reflection did not occur in the adhesion treatment via the adhesive layer. Also, the optical film of the example is much thinner and lighter than the light guide plate of the comparative example, and the accuracy of the shape and arrangement position of the concave portion forming the light emitting means is also compared with the light guide plate of the comparative example. And the visibility, luminance and resolution of the liquid crystal display device were high.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a manufacturing method.
FIG. 2 is an explanatory view of movement of a partial mask (projection mask).
FIG. 3 is an explanatory perspective view of an optical film.
FIG. 4 is an explanatory plan view of another optical film.
FIG. 5
Explanatory drawing of still another manufacturing method
[Explanation of symbols]
1: Laser oscillator
2, 3: Partial mask (projection mask)
21, 31: Opening (laser light transmitting part)
4: Optical equipment
41: Projected image
5: Polymer film (optical film)
51: recess
a: Optical path conversion slope
b: Elevation
7: Mold
8: Optical film
81: recess
a: Optical path conversion slope
b: Elevation

Claims (9)

A laser beam is radiated through a projection mask, and the laser beam transmitted through the projection mask is radiated onto a polymer film by controlling the size of the laser beam through an optical device that creates a projected image. In partially removing by laser etching, the projection mask is formed of at least two partial masks that form a laser light transmitting portion that blocks unnecessary transmission light and shapes the laser light into a quadrilateral. Then, the laser beam transmitting portion is formed into a quadrilateral through an operation of moving a partial mask forming a pair of opposing sides of the quadrilateral of the partial masks in a direction in which the laser beam transmitting portion is closed. An inclined surface characterized by forming a concave portion having a rectangular opening in the polymer surface and a triangular cross-sectional shape in the polymer film as a closed state from a state in which light is formed. Method. The slope forming method according to claim 1, wherein the etching is performed by an ultraviolet laser beam having a wavelength of 400 nm or less. As a projection mask that forms a laser light transmission portion that shapes the laser light into a rectangle, assuming that the partial mask to be moved forms the long side of the rectangle, those partial masks are in a direction parallel to the short side of the rectangle, In addition, the partial mask on one side of the opposite side is moved at a speed of 1.1 to 150 times that of the partial mask on the other side to close the laser light transmitting portion, and laser etching is performed at an etching rate of 0.01 to 5 μm / pulse. The method for forming a slope according to claim 1 or 2, wherein a cross-sectional shape having an optical path conversion slope having an inclination angle of 35 to 48 degrees with respect to the polymer film plane and an elevation having a slope of less than 50 to 90 degrees is a triangle. Forming a light emitting means in which a plurality of the concave portions are discontinuously distributed on one surface of the polymer film by repeating an operation of forming a rectangular concave portion with an opening in the polymer film surface. The method for manufacturing an optical film that. 4. The method according to claim 3, wherein the polymer film is supported on a glass substrate or a metal plate to form light emitting means. 5. The method according to claim 3, wherein the polymer film is a film. The method according to claim 5, wherein the polymer film is made of polyimide. After forming a metal layer by electroforming on the surface of the optical film on which the light emitting means is formed by the manufacturing method according to claim 3, separating the metal layer and the optical film to obtain a mold. A method for manufacturing a mold for forming an optical film. A molding layer in which a radiation-curable resin is adhered to a surface having a convex portion capable of forming a light emitting means in the optical film forming mold according to the manufacturing method according to claim 7, and the shape of the light emitting means is copied. A method for producing an optical film, comprising forming, curing a molded layer by irradiating the molded layer with radiation, and separating the molded layer from a mold. A liquid crystal display device comprising: an optical film according to the manufacturing method according to claim 3 disposed on at least one side of a liquid crystal cell.

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