JP2005257801A - Optical film and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film in which the optimum brightness of an incident image, the degree of freedom in the design of a visual angle, resolution, and contrast are simultaneously improved. <P>SOLUTION: The optical film is provided with a base material film 15 obtained by successively laminating an adhesive layer 12, a light absorption layer 13 and an adhesive layer 14 on one face of a transparent film 11 and light transmissive grains 16 arrayed on the base material film 15, having a major axis direction and a minor axis direction which intersect with each other on a face parallel with the surface of the base material film 15 and having luminous intensity characteristics which are mutually different in both the directions. Since the grains 16 are penetrated through the adhesive layer 14 and the light absorption layer 13 in an arrayed state aligning the major axis direction and at least a part of the grains 16 is intruded into the adhesive layer 12, the scattering of outgoing light has anisotropy and the reflection of external light is prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light that diffuses light from a transmissive screen of a rear projection display device, a viewing angle widening plate such as a liquid crystal display device, a plasma display device, and an electroluminescence display device, a backlight for liquid crystal, and various illumination light sources. The present invention relates to an optical film used as a diffusion plate and a method for producing the same.

  In recent years, in order to support digital broadcasting, high-definition projection display devices using light valves such as liquid crystal panels and digital mirror devices have been developed. There are two types of projection display devices, a front projection type and a rear projection type. The rear projection type has a schematic configuration as shown in FIG. That is, in the rear projection type display device shown in the figure, the image light L projected from the video projection unit 21 which is a projection optical system is magnified and incident on the mirror 22 and reflected by the mirror 22, and then the Fresnel lens. 24 becomes substantially parallel light, and is further diffused left and right by a transmissive screen 27 constituted by a lenticular lens 25. As described above, in the rear projection display apparatus, the image light emitted from the video projection unit 21 is enlarged and projected on the transmission type screen 27 configured by the lenticular lens 25, and the viewer transmits from the opposite side of the video projection unit 21. The light transmitted through the mold screen 27 can be visually recognized as a projected image.

  By the way, the rear projection type display device is usually often installed in a bright room or outdoors. In this case, disturbance light R such as sunlight or indoor lighting is exposed to the surface of the lenticular lens 25 as shown in FIG. There is a problem in that the contrast of the image that is reflected and projected from the transmissive screen together with the image light L is enlarged. Conventionally, as a countermeasure against this, the disturbing light R is absorbed by forming a striped black matrix 26 in a portion other than the exit portion of the lenticular lens 25, and thereby, the contrast of the image is not lowered. Yes.

  However, the transmissive screen using the lenticular lens described above diffuses the image light L in the horizontal direction and obtains a wide viewing angle. However, the image light L is diffused only in a narrow range in the vertical direction. Has a drawback that the viewing angle is narrower than the horizontal direction. In order to solve this drawback, two lenticular lenses 25 are superposed vertically so that a wide viewing angle can be obtained in any of the horizontal and vertical directions, but the number of parts increases and the thickness of the transmission screen itself is increased. In addition, a new problem of multiple reflection between multiple layers occurs, and the design and configuration of the lens becomes difficult. Further, when the black matrix 25 is provided to improve the contrast, the area ratio of the external light absorbing portion is about 30% from the viewpoint of the utilization efficiency of the image light L, and it is difficult to further improve the contrast of the image.

  In order to solve the above problems, a transmissive screen using a flat lens in which transparent micro beads are arranged two-dimensionally is attracting attention as an alternative to the lenticular lens 25 (for example, US Pat. Nos. 5,563,738 and S6,204,971). B1), research and development for practical application of large-screen high-definition displays is being conducted. FIG. 12 shows a rear projection projector that employs a transmissive screen using the planar lens. In the figure, the image light L projected from the video projection unit 31 is reflected by the mirror 32, becomes parallel light by the Fresnel lens 33, and is diffused forward through the planar lens 34. The planar lens 34 is configured by two-dimensionally closely packing a large number of transparent microbeads 35, and the transparent microbeads 35 can diffuse the image light L over a wide range in the horizontal and vertical directions. Further, the area ratio of the external light absorbing portion can be made higher than in the case of the transmission type screen constituted by the lenticular lens shown in FIG. 10, and the contrast of the image can be improved.

  By the way, in the rear projection television apparatus, usually only a limited amount of incident light can be obtained due to a reduction in power consumption. For this reason, it is required to increase the brightness of the image by diffusing the emitted light only in necessary portions. Particularly in a home display, even if the viewer moves in the left-right direction (horizontal direction) of the display, it rarely moves in the vertical direction, and even if it moves, the distance is small. For this reason, in a transmissive screen, the viewer can move horizontally (horizontal direction) by increasing the horizontal diffusion angle, that is, by increasing the viewing angle in the horizontal direction, compared to the diffusion angle of emitted light in the vertical direction. It is desirable to realize a bright image even when moving to.

  In this regard, in the transmissive screen of FIG. 12, a large number of transparent microbeads 35 are two-dimensionally closely packed and arranged, so that the distribution density of the image light L on the exit surface of the planar lens 34 is high. However, since the transparent microbeads 35 are spherical and the emitted image light L is diffused only isotropically, the distribution of the emitted light with respect to the incident light has no anisotropy. There is a problem in that light diffuses over a wide area and the image becomes dark and the contrast of the image decreases. On the other hand, in the transmissive screen having the lenticular lens 25 shown in FIG. 11, the light distribution of the emitted light is anisotropic with respect to the incident light, and the horizontal light diffusion angle is increased and the horizontal direction is increased. The viewing angle can be increased. However, in order to increase the resolution by reducing the pitch of the cylindrical lenses 26a and 26b in the lenticular lens 25, the lenticular lens 25 itself needs to be thinned. However, if the pitch is 100 μm or less, a lens shape is formed. It becomes difficult. Further, since the lenticular lens 25 hardly diffuses light in the vertical direction, a diffusion plate or the like is required as a separate part for diffusion in the vertical direction.

Thus, in the above-described conventional transmission screen, even when the lenticular lens 25 is used as shown in FIG. 11 or when the transparent microbeads 35 are used as shown in FIG. It was difficult to increase the design freedom, resolution, and contrast at the same time. As a suggestion for solving these problems, there is a report example of a transmission screen in which a large number of spheroids made of fine particles are arranged in the same direction instead of the transparent fine beads (see, for example, Patent Document 1). ).
JP-A-11-133512

  However, this screen is just an array of a large number of spheroids made of resin or glass microparticles on one surface of a transparent substrate, and efficiently absorbs disturbance light such as sunlight and room lighting. Since the structure is not possible, a satisfactory image cannot be obtained particularly in terms of the contrast of the image. In addition, there is no description of a manufacturing method that can stably supply a large amount of such a high-quality transmission screen.

  Therefore, the present invention provides an optical film capable of realizing a large viewing angle in the horizontal direction and realizing excellent resolution and contrast when used as a transmissive screen of a rear projection display device, for example, and a method for manufacturing the same. For the purpose.

  In order to achieve the above object, an optical film according to the present invention includes a base film in which an adhesive layer, a light absorption layer, and an adhesive layer are stacked in this order on one side of a transparent film, and the base film is arranged on the base film. Light-transmitting particles having a major axis direction and a minor axis direction perpendicular to each other and having different light distribution characteristics in both directions, and the particles are arranged with the major axis direction aligned. The layer penetrates and at least a part of the layer penetrates the adhesive layer.

  According to this configuration, light transmissive particles having a major axis direction and a minor axis direction orthogonal to each other in a plane parallel to the base film surface and having different light distribution characteristics in both directions are aligned in the major axis direction. In such a state, the light passes through the adhesive layer and the light absorption layer and at least part of the adhesive layer penetrates the adhesive layer, so that when light enters from the particle side and exits from the transparent film side, the emitted light is Output with anisotropy. That is, there is anisotropy in the light distribution of the outgoing light with respect to the incident light, and the density of the light distribution of the outgoing light can be increased by increasing the arrangement density of the particles. The viewing angle when this optical film is applied as a transmissive screen of a rear projection display device can be improved, and the resolution can be increased. In addition, since the light-transmitting particles are fixed by the adhesive layer, the light absorption layer and the adhesive layer of the base film, there is less possibility of detachment from the base film or missing, and the life as an optical film can be extended. . In addition, disturbance light such as sunlight and indoor certification is incident on the optical film from the transparent film side of the base film and reaches the light absorption layer. However, most of the disturbance light is absorbed here and hardly becomes stray light. For this reason, when this optical film is used as a transmission screen of a rear projection display device, the image becomes bright and the contrast of the image can be improved.

  In a preferred embodiment of the present invention, at least approximately half of the light transmissive particles are exposed from the base film, and the remaining portion penetrates the light absorption layer having a lower refractive index than the light transmissive particles. And the adhesive layer has been reached.

  According to this configuration, desired light distribution characteristics can be easily obtained by appropriately setting the major axis direction and minor axis direction dimensions of the light transmissive particles. Moreover, since almost half of the particles are exposed, the amount of incident light can be increased. Further, since the remaining part of the particle passes through the light absorption layer having a refractive index lower than that of the particle and reaches the adhesive layer, the light incident on the particle is refracted and condensed and absorbed by the light absorption layer. Then, the light is transmitted to the transparent film surface side without being shielded from light. Therefore, the light use efficiency of the optical film is improved.

  In a preferred embodiment of the present invention, the refractive index of the light transmissive particles is in the range of 1.4 to 2.0.

  According to this configuration, the incident image light first enters the light-transmitting particles. At this time, since the refractive index of the particles is in the range of 1.4 to 2.0, the light collecting performance due to refraction. And the light use efficiency of the optical film is improved accordingly. If the refractive index is less than 1.4, sufficient refractive power cannot be obtained, and if it exceeds 2.0, the transmittance tends to decrease due to an increase in backscattering.

  In a preferred embodiment of the present invention, the light transmissive particles are spheroids having a major axis as a rotation axis, and a ratio of the minor axis to the major axis is in a range of 1: 5 to 1: 1.5. The length of the long axis is 100 μm or less.

  According to this configuration, since the length in the major axis direction of the particles is 100 μm or less, for example, it is easy to fill the base film in the major axis direction with a high density by the method described later. As a result, the density of the light distribution of the emitted light can be increased and the resolution can be increased. Further, since the ratio of the minor axis to the major axis to the minor axis of the spheroid is in the range of 1: 5 to 1: 1.5, light distribution characteristics suitable for an image screen can be obtained. When the ratio between the major axis and the minor axis is large, the anisotropy is strong, the light is dispersed less in the direction of less light distribution, and the image light becomes brighter. Becomes weaker and the image light becomes darker.

  The method for producing an optical film according to the present invention includes a step of forming an adhesive layer on a transparent film, a step of forming a light absorbing layer on the adhesive layer, and an adhesive layer on the light absorbing layer. The process arranges the particles with a long axis perpendicular to the adhesive layer by applying a high voltage to light transmissive particles having a major axis direction and a minor axis direction orthogonal to each other and different light distribution characteristics in both directions. And the step of rotating the particles so that the major axis thereof is substantially parallel to the base film including the adhesive layer, the light absorbing layer, and the adhesive layer, penetrating the light absorbing layer and at least partly the adhesive layer And a process of intruding into.

  According to this structure, the base film which piled up the adhesion layer, the light absorption layer, and the contact bonding layer in this order on the single side | surface of the transparent film at the front | former process is produced. Subsequently, by applying a high voltage to the light transmissive particles in a later step, the particles are arranged on one side of the base film so that the major axis thereof is perpendicular to the electrostatic flocking. After that, for example, the roller is pressed so that the long axis of the particles is substantially parallel to the base film, and at least part of the particle penetrates the adhesive layer through the light absorption layer. Since the subsequent manufacturing process can be continued, the optical film can be manufactured at low cost. Depending on the voltage applied to the particles and the amount of light transmissive particles supplied, the pitch between the vertically implanted particles can be set arbitrarily. For example, by adjusting the roller pressing force, the particles can penetrate to the predetermined depth of the light absorption layer. Therefore, it is easy to adjust the characteristics.

  According to the optical film of the present invention, it is possible to provide an optical film having a large viewing angle in the horizontal direction and capable of realizing excellent resolution and contrast at a low cost, for example, as a transmission screen of a rear projection display device. When used, diffuse reflection due to disturbance light is reduced, and a bright and high-contrast image can be obtained.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of an optical film according to an embodiment of the present invention. An optical film 10 shown in FIG. 1 is arranged on a base film 15 in which an adhesive layer 12, a light absorption layer 13 and an adhesive layer 14 are stacked in this order on one surface of a transparent film 11, From the spheroid 16 which is an example of light-transmitting particles having a major axis direction and a minor axis direction perpendicular to each other in a plane parallel to the main surface of the substrate film 15 and having different light distribution characteristics in both directions. It is configured. In this example, the particles 16 are spheroids having a major axis as a rotation axis. As shown in FIG. 2, the particles 16 are arranged in a densely aligned manner in the major axis direction as shown in FIG. As described above, with the plane including the long axis as a boundary, half is exposed from the base film 15, the other half penetrates the adhesive layer 14 and the light absorption layer 13, and at least part of the adhesive layer 12 penetrates. Yes. Thereby, the outer peripheral part of the particle | grains 16 contacts the light absorption layer 13. FIG.

  As the transparent film 11 constituting the base film 15, for example, a film formed of a resin having excellent transparency such as an acrylic resin, a polycarbonate resin, a vinyl chloride resin, a polyolefin resin, or a polyester resin is used. The pressure-sensitive adhesive layer 12 is made of a double-sided adhesive film, and is stuck on one side of the transparent film 11.

  It is preferable that the light emission surface side of the base film 15, that is, the light emission surface 11 a of the transparent film 11 is subjected to an antireflection treatment. For example, in the antireflection treatment, the antireflection layer is formed to a predetermined thickness by coating or vacuum deposition. In addition, in the anti-glare treatment for the purpose of preventing reflection, by forming irregularities on the light emitting surface 11a by a method of coating by mixing silica, plastic beads or the like into a resin, or by sandblasting or embossing shaping, An antireflection treatment may be performed.

  As the transparent film, a rigid transparent substrate may be used, or a transparent film may be bonded to a rigid transparent substrate having an antireflection function via an adhesive.

  The light absorbing layer 13 is formed by coating the adhesive layer 12 with a predetermined amount of a black ink or a black pigment mixed with a photocurable resin or a thermosetting resin having a refractive index lower than that of the light transmissive particles 16. It is formed by applying heat or curing by ultraviolet irradiation. The light absorption layer 13 plays a role as a conventional black matrix by blending the black ink or black pigment.

  The adhesive layer 14 is formed by coating the light absorbing layer 13 with an adhesive having a main component of the same resin as the photocurable resin or thermosetting resin constituting the light absorbing layer 13. However, it is possible to use any material that has excellent adhesiveness and a refractive index lower than that of the light-transmitting particles 16.

  The light transmissive particles 16 are formed from a resin or glass having excellent transparency, and the refractive index is preferably in the range of 1.4 to 2.0. The spheroid, which is an example of the light-transmitting particles 16, preferably has an average diameter in the major axis direction of 100 μm or less. Since the anisotropy of the light distribution of the emitted light with respect to the incident light can be adjusted by appropriately changing the diameter in the major axis direction and the diameter in the minor axis direction of the spheroid, the degree of freedom in designing the viewing angle is high.

  The ratio of the minor axis to the major axis of the spheroid which is the light-transmitting particle 16 is in the range of 1: 5 to 1: 1.5, preferably in the range of 1: 3.0 to 1: 1.5. To do. Description of optical film characteristics when the ratio of the minor axis to the major axis (aspect ratio) of the spheroid is changed to 1: 3.0, 1: 2.5, 1: 2.0, 1: 1.5. To do. For example, the luminance distribution in both the vertical and horizontal directions when the aspect ratio is 1: 3.0 is as shown in FIG. Here, the major axis direction of the particles 16 is matched with the horizontal direction. As shown in FIG. 4, the luminance b in the horizontal direction is higher than the luminance a in the vertical direction over a wide range of angles. The vertical luminance distribution when the aspect ratio (1: n) is changed to n = 3.0, n = 2.5, n = 2.0, n = 1.5, and n = 1 (spherical) is As shown in FIG. 5, as the n value increases, the diffusion of light in the vertical direction (short axis direction) decreases, so the maximum luminance value increases, but the luminance decreases in a region with a large vertical viewing angle. Thus, when n = 1 (spherical) for comparison, the highest luminance value is the lowest (a1), and the luminance in the region with a large vertical viewing angle is higher than that of the spheroid (a1 to a4). ing.

  Next, the ratio of the major axis to the minor axis (aspect ratio) of the spheroid is changed to 1: 3.0, 1: 2.5, 1: 2.0, 1: 1.5. The use efficiency and the printable area ratio (BM ratio) of the black matrix composed of the light absorption layer will be described. As can be seen from the comparison between FIG. 1 and FIG. 3, in the case of FIG. 1 in which the n value of the aspect ratio 1: n of the spheroid which is the light-transmitting particle 16 is small, the light absorption layer 13 is the lower surface (anti-exposed) of the particle 16. As a result of approaching the center (short axis) of the surface), the printable area ratio (BM ratio) of the black matrix becomes larger than in the case of FIG. 3 where the n value is large. That is, as shown in FIG. 6, as the n value is smaller, the BM ratio tends to increase, and the emission efficiency against light incidence (light utilization efficiency) and the black matrix (BM) in the vertical direction prevent the emission. There is a tendency for the angle to decrease. When the aspect ratio is large, the anisotropy becomes strong, and the diffusion of light in the vertical direction (vertical direction) decreases and the image light becomes bright. When the aspect ratio is small, the anisotropy becomes weak and the light in the vertical direction The diffusion of light increases and the image light becomes dark.

  On the other hand, in the case of the conventional spherical transparent microbeads (n = 1 and aspect ratio 1: 1), the printable area ratio (BM ratio) of the black matrix is large, and the emission efficiency with respect to the incidence of light (light Utilization efficiency) and the angle at which the emission is hindered by the BM in the vertical direction increases. In this way, since an optical film having various characteristics can be obtained by selecting the aspect ratio of the spheroid, free optical design is possible. The light-transmitting particles in the above configuration are spheroids, but instead, the shape has anisotropy, such as a shape in which the spheroids are divided into two equal parts on a plane including the long axis, or an egg shape. Can be used.

  1 is disposed on the exit side of the Fresnel lens 24 as described in FIG. 10, and the parallel light from the Fresnel lens 24 is vertically incident thereon. As shown in FIG. 3, the spheroids that are the light-transmitting particles 16 are densely arranged on one side of the base film 15 so that the major axis directions thereof are parallel to each other. The resolution can be easily increased by reducing the size. Further, since the spheroid which is the light-transmitting particle 16 penetrates the adhesive layer 14 and the light absorption layer 13 and at least part of the spheroid has penetrated the adhesive layer 12, light incident perpendicularly to the particle 16 ( The image light (L) is refracted and collected, passes through the adhesive layer 12 without being absorbed by the light absorption layer 13, and exits as image light from the transparent film 11 side. In this way, almost all of the vertically incident light becomes image light, and bright image light is obtained.

  The optical film according to the above configuration enables display with high definition and contrast while maintaining the brightness of the image. Therefore, when this optical film is used as a transmissive screen in a rear projection display device, diffuse reflection due to ambient light is reduced, and a bright image with high resolution and contrast can be obtained.

  Next, a method for manufacturing the optical film according to an embodiment of the present invention will be described with reference to the drawings. In producing the base film shown in FIG. 1, first, a spheroid that becomes the base film 15 and the light-transmitting particles 16 is prepared. In the first step, the base film 15 shown in FIG. 7 is produced. First, as the transparent film 11, a film having a thickness of 0.25 mm made of polyethylene terephthalate resin is used, and an adhesive layer 12 is formed by sticking a double-sided adhesive tape having a thickness of 0.1 mm on one surface. Subsequently, a photocurable resin blended with a black pigment was applied onto the adhesive layer 12 with a knife coater, coated, dried at 60 ° C. for 10 minutes, and then a polyethylene-treated terephthalate film (thickness 0.075 mm). ) Is laminated on the photocurable resin. Then, the light absorption layer 13 in which the photocurable resin is ultraviolet-cured is formed by irradiating the polyethylene terephthalate film with ultraviolet light of 500 mJ / irradiation and peeling the polyethylene terephthalate film. Further, a base film 15 was obtained by spraying a sol-like adhesive on the light absorption layer 13 and applying or coating with a bar coater to form an adhesive layer 14 having a thickness of several μm.

  Subsequently, in the second step, a spheroid that becomes the light transmissive particles 16 of FIG. 1 is produced. First, non-crosslinked polystyrene particles having a uniform particle size (average 45 μm) were prepared by a membrane emulsification method, and the prepared particles were made of polyvinyl alcohol (suspension degree 78.5-80.5%, polymerization degree 2000) resin isopropyl alcohol: distilled water = Dissolve in 1: 1 solvent, uniformly disperse non-crosslinked polystyrene in the solution, and after casting into a polyvinyl alcohol film in which particles are uniformly dispersed, heat-stretch the polyvinyl alcohol film at 120 ° C in a uniaxial direction. Then, the non-crosslinked polystyrene particles are transformed into the spheroid 161. By dissolving the heat-stretched film with water, a polystyrene spheroid 161 having a uniform size and light-transmitting particles 16 was obtained.

  Thus, after producing the spheroid 161 used as the base film 15 and the light transmissive particle | grains 16, as shown in FIG. 8, electrostatic flocking by polarization is performed as a 3rd process. In FIG. 8, the base film 15 is set to be the counter electrode P2 with respect to one electrode P1, and a DC high voltage is applied thereto. When the polystyrene spheroid 161, which is a light transmissive particle 16, is supplied between the electrodes P1, P2, the polystyrene spheroid 161 in various directions is inverted as indicated by an arrow Q by electrostatic force. And it scatters along an electric force line and pierces on the adhesive layer 14 surface of the base film 15. In this manner, a film in which polystyrene spheroids are vertically arranged on the adhesive layer 14 of the base film 15 is formed.

  Further, in the fourth step, as shown in FIG. 9, the spheroid 161 arranged on the substrate film 15 is rotated by rotating a roller 18 whose metal surface is coated with hard rubber in the direction of arrow 17 to 25 kgf / By applying the pressure c, the spheroid 161 changes from a state perpendicular to the base film 15 to a substantially parallel state and is arranged in a uniaxial direction along the major axis. A part of the adhesive layer 14 and the light absorption layer 13 penetrates and part of the adhesive layer 12 penetrates into the adhesive layer 12 so that the spheroids 161 are arranged in a uniaxial direction on the base film 15 as shown in FIG. The obtained optical film 10 was obtained. The filling ratio of the spheroid 161 to the base film 15 can be arbitrarily adjusted by the conductivity of the adhesive 14 and the material of the spheroid 161.

  As mentioned above, according to the manufacturing method of the optical film by this invention, since the said 1st-4th process can be manufactured with the continuous manufacturing process, it becomes possible to manufacture the optical film 10 at low cost. .

It is a horizontal sectional view showing an optical film concerning one embodiment of the present invention. It is a front view which shows the same optical film. It is a horizontal sectional view showing light condensing by a spheroid. It is a graph which shows the relationship between the viewing angle in an optical film, and the intensity | strength of emitted light. It is a graph which shows the change of the vertical viewing angle and the intensity | strength of emitted light by the aspect-ratio of a spheroid. It is a graph which shows the correlation of the aspect-ratio of a spheroid, the utilization efficiency of light, and the area ratio which can print a black matrix. It is typical sectional drawing of the base film in an optical film. It is a typical schematic diagram which shows a mode that a spheroid is electrostatically flocked to a base film in a perpendicular | vertical array state. It is a typical schematic diagram of the process of horizontally arranging the vertically arranged spheroids by roller pressing. It is the schematic which shows the conventional rear projection type display apparatus. It is a schematic sectional drawing of the lenticular lens and Fresnel lens in the conventional rear projection type display apparatus. It is the schematic which shows the rear projection type display apparatus which employ | adopted the transmission type screen by the conventional flat type lens.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical film 11 Transparent film 12 Adhesive layer 13 Light absorption layer 14 Adhesive layer 15 Base film 16 Light-transmitting particle 161 Spheroid L Image light

Claims (5)

A base film in which an adhesive layer, a light absorbing layer and an adhesive layer are laminated in this order on one side of a transparent film;
Light-transparent particles arranged on the base film and having a major axis direction and a minor axis direction orthogonal to each other in a plane parallel to the base film surface and having different light distribution characteristics in both directions ,
An optical film in which the particles penetrate the adhesive layer and the light absorption layer in a state where the long axis direction is aligned, and at least a part of the optical film penetrates into the adhesive layer.   In claim 1, at least approximately half of the light transmissive particles are exposed from the base film, the remaining portion penetrates the light absorption layer having a lower refractive index than the light transmissive particles, An optical film that reaches the adhesive layer.   3. The optical film according to claim 2, wherein the refractive index of the light transmissive particles is in the range of 1.4 to 2.0.   4. The light-transmitting particle according to claim 2, wherein the light-transmitting particle is a spheroid having a major axis as a rotation axis, and the ratio of the minor axis to the major axis is in the range of 1: 5 to 1: 1.5. An optical film having a shaft length of 100 μm or less. Forming an adhesive layer on the transparent film;
Forming a light absorption layer on the adhesive layer;
Forming an adhesive layer on the light absorbing layer;
Applying a high voltage to light-transmitting particles having a major axis direction and a minor axis direction orthogonal to each other and having different light distribution characteristics in both directions, and arranging the particles with the major axis perpendicular to the adhesive layer; ,
The step of rotating the particles so that the major axis thereof is substantially parallel to the base film including the adhesive layer, the light absorbing layer and the adhesive layer, penetrating the light absorbing layer and causing at least a part of the particles to enter the adhesive layer When,
The manufacturing method of the optical film provided with.

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