JP2006163377A - Combination optical film, laminated combination optical film and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combination optical film which is the combination optical film made by mutually put together end faces of a plurality of optical films, does not spoil external appearance and prevents occurrence of light leak. <P>SOLUTION: In the combination optical film which is made by mutually put together at least one end faces of the plurality of optical films, mutual shapes of the end faces being put together are approximately matched with each other and the put together end faces have at least portions which are not normal with respect to the surface and the back surface of the optical films. The put together end faces are put together from the surface to the back surface along the normal direction of the optical film so that no continuous gap is created. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a combined optical film formed by abutting end surfaces of a plurality of optical films. Moreover, this invention relates to the lamination | stacking combination optical film which laminated | stacked the combination optical film. The present invention also relates to an image display device such as a liquid crystal display device, an organic EL display device, and a PDP using the combination optical film or the laminated combination optical film.

  Examples of the optical film include a polarizer, a protective film laminated on one or both sides of the polarizer, a polarizing plate obtained by laminating the protective film on one or both sides of the polarizer, a retardation plate, an optical compensation film, and a brightness enhancement film. can give. These optical films can be used alone or in combination as a laminated optical film. The laminated state may include a combination type optical film. Moreover, what was used as the said combination optical film for each said optical film can be laminated | stacked and used.

  An optical film typified by a polarizing plate or the like is used for an image display typified by a liquid crystal display device or the like used for a television or a personal computer. In recent years, televisions and the like have been increased in size, and optical films having a large area have been required. In order to manufacture a large-area optical film, a large-scale manufacturing facility is required. Further, it is difficult to handle the packaging, and much cost is required. In addition, a large space is required to install the large manufacturing facility. Therefore, a technique for forming a large liquid crystal display device by arranging a plurality of liquid crystal display devices and abutting the end faces thereof has been proposed.

However, liquid crystal display devices such as televisions and personal computers use the function of an optical film such as a polarizing plate to perform display by transmitting and blocking (absorbing) light from the back surface. When the end surfaces are butted, there is a problem that light leakage occurs at the butting portion and light streaks occur on the surface of the liquid crystal display device. For this, as shown in FIG. 21, a film F is pasted from above the polarizing plate (optical film A) to the abutting portions (between xx of the abutting end surfaces) of a plurality of liquid crystal display devices. A technique for preventing light leakage has been disclosed (Patent Document 1). However, although the technique of Patent Document 1 can prevent light leakage, there is a problem that the surface appearance of the liquid crystal display device is impaired by the film attached to the surface of the polarizing plate.
JP-A-5-88163

  An object of the present invention is to provide a combined optical film in which end surfaces of a plurality of optical films are brought into contact with each other and capable of preventing light leakage without impairing the appearance.

  Another object of the present invention is to provide an image display device using the combined optical film.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the object can be achieved from a combination optical film shown below, and have completed the present invention.

That is, the present invention is a combined optical film formed by abutting at least one end face of a plurality of optical films with each other,
The butted end surfaces substantially match each other in shape, and the butted end surfaces have at least portions that are not perpendicular to the front and back surfaces of the optical film,
The butted end surface relates to a combination type optical film (1) characterized in that the butted end surfaces are butted so as not to have a continuous gap from the front surface to the back surface in the normal direction of the optical film.

  According to the combined optical film (1), the abutting end faces have portions that are substantially matched to each other and that are not perpendicular to the front and back surfaces of the optical film. In the normal direction of the film, they are abutted so as not to have a continuous gap from the front surface to the back surface. The butted end faces preferably have the same shape as each other. With such a structure, light leakage from the butted portion can be prevented without causing a gap in the vertical direction between the front surface and the back surface of the butted portion. Thus, by devising the shape of the butt end face, light leakage can be prevented without applying a film. Therefore, when the combined optical film is applied to a liquid crystal display device or the like, light leakage due to irradiation light from the back surface can be suppressed without impairing the surface appearance.

  In the combined optical film (1), the butt end surface may be one that is inclined in a plane from the front surface to the back surface of the optical film.

  Various shapes can be used for the butt end surface, but the flat inclined butt end surface is easy to process, and in the production of a combined optical film, the operation when combining the butt end surfaces is easy. is there.

  In the combined optical film (1), the inclination angle (θ) of the butted end surface is preferably 1 to 89 ° between the end surface and the normal direction to the optical film. The inclination angle (θ) of the butted end surfaces is not particularly limited, but is preferably within the above range in consideration of light leakage and ease of processing, operation in combination, and the like. More preferably, it is 5-75 degrees, More preferably, it is 10-65 degrees.

Further, when the inclination angle of the butt end face is θ (°), the average gap between the films in the butt portion is t (μm), and the thickness of the optical film is d (μm),
t ≦ d × tan θ,
1 ° ≦ θ ≦ 60 °,
It is preferable to satisfy this relationship.

  Since the inclination angle θ varies depending on the type and thickness d and optical characteristics of the optical film, or the use state of the optical film, it can be designed as appropriate. For example, when the combination-type optical film according to the present invention is provided on the viewing side of the liquid crystal cell when applied to a liquid crystal display device, light leakage tends to occur when viewed from the front direction. It is preferable to satisfy the relationship of × tan θ. The gap t is the average value of the gaps at the butted portion of the combined optical film.

  In general, the inclination angle θ for use in an image display apparatus for TV applications and the like is preferably as large as possible because the angle of the field of view where light leakage is less likely to occur. From this viewpoint, the inclination angle θ is preferably 45 ° or more, more preferably 60 ° or more, and further preferably 75 ° or more. Further, when used in a liquid crystal display device that does not require a large viewing angle, such as a notebook computer, the inclination angle θ may be about 30 ° or more, and more preferably 45 ° or more. On the other hand, considering the ease of processing when abutting the optical film, it is preferable that the inclination angle is small. When the inclination angle θ is too large, the abutting portions are likely to ride on each other during the abutting operation, or a step is generated, making it difficult to obtain a combined optical film having a certain size. From this point of view, the inclination angle θ is preferably 1 ° or more, further 5 ° or more, more preferably 10 ° or more, and further preferably 15 ° or more. From both viewpoints, it is preferable that the inclination angle θ satisfies 1 ° ≦ θ ≦ 60 °. Furthermore, 10 ° ≦ θ ≦ 60 ° and 15 ° ≦ θ ≦ 60 ° are preferable.

The present invention also relates to a combination type optical film formed by abutting at least one end face of a plurality of optical films with each other.
The butted end face relates to a combined optical film (2) characterized in that it is bonded with a bonding agent having substantially the same refractive index as that of the optical film.

  According to the combined optical film (2), the butt end surface is bonded with a bonding agent having substantially the same refractive index as that of the optical film, and the adhesive is covered in the gap between the butt portions. Appearance loss can be improved, and the refractive index of the bonding agent is substantially the same as that of the optical film, so visibility is not hindered. Therefore, when the combined optical film is applied to a liquid crystal display device or the like, light leakage due to irradiation light from the back surface can be suppressed without impairing the surface appearance.

The present invention also relates to a combination type optical film formed by abutting at least one end face of a plurality of optical films with each other.
The butted end face relates to a combined optical film (3) characterized in that it is bonded by dissolution and solidification with an organic solvent capable of dissolving the optical film.

  According to the combined optical film (3), the butt end face is joined by dissolution and solidification with an organic solvent capable of dissolving the optical film, so the butt portion is melt-joined without a gap, and the appearance loss due to the gap In addition, since the bonding is performed by dissolving the optical film, the visibility is not hindered. Therefore, when the combined optical film is applied to a liquid crystal display device or the like, light leakage due to irradiation light from the back surface can be suppressed without impairing the surface appearance.

The present invention also relates to a combination type optical film formed by abutting at least one end face of a plurality of optical films with each other.
The butted end face relates to a combination type optical film (4) characterized by being bonded by thermal fusion.

  According to the combined optical film (4), since the butt end surfaces are bonded by thermal fusion of the optical film, the butt portion is melt bonded without a gap, and appearance loss due to the gap can be improved. It can be made and the bonding is performed by melting the optical film, so that the visibility is not hindered. Therefore, when the combined optical film is applied to a liquid crystal display device or the like, light leakage due to irradiation light from the back surface can be suppressed without impairing the surface appearance.

The present invention also relates to a combination type optical film formed by abutting at least one end face of a plurality of optical films with each other.
The plurality of optical films relates to a combination type optical film (5) characterized by having a diffusion layer and / or an optical film on the front surface and / or the back surface.

The present invention also relates to a combination type optical film formed by abutting at least one end face of a plurality of optical films with each other.
The present invention relates to a combined optical film (6) characterized in that a diffusion layer and / or an optical film are provided on the front surface and / or back surface of the combined optical film.

  As in the above combined optical films (5) and (6), those with a diffused layer can diffuse light in the diffused layer, making the joint between the butt end faces inconspicuous and improving visibility. can do. In addition, instead of the diffusion layer or together with the diffusion layer, a layer in which a brightness enhancement film is laminated as an optical film is used, for example, in a combination polarizing plate, a brightness enhancement film (linearly polarized light separating film) is placed between the polarization plate and the backlight. By arranging so as to become, it is possible to make the joint of the butt end faces inconspicuous. Further, in the combined optical films (5) and (6), the butt end surface can have the same structure as the combined optical films (1), (2), (3), and (4). Thereby, visibility can be improved.

  In the combined optical films (1), (2), (3), (4), (5), and (6), the thickness of the optical film is preferably 500 μm or less. Furthermore, the thickness of the optical film is preferably 300 μm or less. If the thickness of the optical film exceeds 500 μm, the elasticity of the film is high, so that problems such as difficulty in bonding to the liquid crystal panel tend to occur.

  In the combination optical films (1), (2), (3), (4), (5), and (6), various optical films can be used. A polarizing plate having a protective film laminated on one or both sides of a polarizer or a polarizer is preferably used. That is, as an optical film, a polarizer or a protective film for a polarizer can be used alone, respectively, and can also be applied to a polarizing plate in which a protective film is laminated on one or both sides of a polarizer. .

As described above, a combination-type polarizing plate using a polarizing plate as an optical film has the combination-type polarizing plate disposed on the backlight side of the liquid crystal cell, while the viewing side of the liquid crystal cell has a polarizing plate (combination). The difference between the central luminance A (cd / cm ² ) of the butt portion of the combined polarizing plate and the peripheral luminance B (cd / cm ² ) measured for the liquid crystal panel arranged in crossed Nicols (central luminance A− The peripheral luminance B) is preferably ²⁰ cd / cm ² or less. The difference is more 15 cd / cm ² or less, further 10 cd / cm ² or less, more preferably at 5 cd / cm ² or less. The smaller the difference, the smaller the light leakage.

  Moreover, in said combination type optical film (1), (2), (3), (4), (5), (6), a phase difference plate can also be provided as an optical film.

As described above, a combination type retardation plate using a retardation plate as an optical film is a polarizing plate (not combined) on both sides of the combination type retardation plate disposed adjacent to the liquid crystal cell on the backlight side. ) Is arranged in crossed Nicols, and the liquid crystal panel is arranged so that the absorption axis of the polarizing plate on the backlight side is substantially parallel to the slow axis of the combined retardation plate The difference between the center luminance A (cd / cm ² ) and the peripheral luminance B (cd / cm ² ) of the butted portion of the combined retardation plate (center luminance A−peripheral luminance B) is 20 cd / cm ² or less. Preferably there is. The difference is more 15 cd / cm ² or less, further 10 cd / cm ² or less, more preferably at 5 cd / cm ² or less. The smaller the difference, the smaller the light leakage.

  In the combined optical films (1), (2), (3), (4), (5), (6), the plurality of optical films are easily peelable on the front surface and / or back surface. A film is attached, and an adhesive tape is affixed on the adjacent protective film corresponding to the abutting portion in the combination type optical film, and the protective films are connected to each other. .

  When attaching an easily peelable protective film to the front or back surface of the plurality of optical films, the protective film is peeled off by attaching an adhesive tape to the protective films and joining the protective films together. Sometimes, the adjacent protective films can be peeled at once, and the troublesome peeling work can be simplified.

  The present invention also provides a laminated combined optical film (1), (2), (3), (4), (5), and (6) laminated at least two layers. 11).

  The combination optical films (1), (2), (3), (4), (5), and (6) can be used by laminating each other. 11) has the same effects as the combination type optical films (1), (2), (3), (4), (5), and (6).

Further, the present invention is a laminated combined optical film formed by laminating a plurality of combined optical films obtained by abutting at least one end face of a plurality of optical films,
The laminated combined optical film (12) is characterized in that at least one butt portion of the combined optical film of each layer is laminated so as not to overlap in the normal direction to the combined optical film.

  According to the above laminated combined optical film (12), since the combined optical films are laminated so that the respective butted portions do not overlap, even if there is a gap in each butted portion, the gap Is shielded by other layers in the entire laminated combined optical film (12). As a result, in the laminated combination type optical film (12), between the front surface and the back surface, no gap is generated in the direction perpendicular to the front surface to the back surface, and light leakage from the butted portion can be prevented. Therefore, when the laminated combined optical film (12) is applied to a liquid crystal display device or the like, light leakage due to irradiation light from the back surface can be suppressed without impairing the surface appearance.

  In the laminated combined optical film (12), the combined optical film having at least one layer can have the same configuration as the combined optical films (1), (2), (3), and (4). Thereby, light leakage can be prevented more effectively without impairing the appearance.

  In the laminated combined optical films (11) and (12), the plurality of optical films forming the combined optical film on the front surface and / or the back surface are on any one of the front surface, the back surface, and the inner surface. What has a diffused layer and / or an optical film can be used.

  Further, in the laminated combination optical films (11) and (12), a laminated combination optical film having a diffusion layer and / or an optical film on any one of the front surface, the back surface, and the inner surface is used. Can do.

  What laminated | stacked the diffusion layer on the said lamination | stacking combination type | mold optical film (11), (12) diffuses light in a diffusion layer in addition to having the said effect, and makes the joint of a butt | matching end surface inconspicuous. And visibility can be further improved. In addition, instead of the diffusion layer or together with the diffusion layer, a layer in which a brightness enhancement film is laminated as an optical film is used, for example, in a combination polarizing plate, a brightness enhancement film (linearly polarized light separating film) is placed between the polarization plate and the backlight. By arranging so as to become, it is possible to make the joint of the butt end faces inconspicuous.

  In the laminated combined optical films (11) and (12), the thickness of the optical film in each layer is preferably 500 μm or less. Furthermore, the thickness of the optical film is preferably 300 μm or less. If the thickness of the optical film exceeds 500 μm, the elasticity of the film is high, so that problems such as difficulty in bonding to the liquid crystal panel tend to occur.

  In the laminated combination optical films (11) and (12), various kinds of optical films can be used. For example, as an optical film in a single layer combination optical film, a polarizer is used. As the optical film in the combination optical film having at least one layer, a laminated combination optical film (11), (12) can be used as a polarizing plate by using a protective film for a polarizer.

  In the laminated combined optical films (11) and (12), a polarizing plate can be selected and used as the optical film used for the combined optical film of each layer.

As described above, a laminated combination type polarizing plate in which a polarizing plate is formed by combining each layer, or a laminated combination type polarizing plate using a polarizing plate as a combination type optical film of each layer, the laminated combination type polarizing plate is used for a liquid crystal cell. Center luminance A (cd) of the butt portion of the laminated combined polarizing plate measured on the liquid crystal panel in which the polarizing plate (not combined) is arranged in crossed Nicols on the viewing side of the liquid crystal cell. / Cm ² ) and the peripheral luminance B (cd / cm ² ) (center luminance A−peripheral luminance B) is preferably ²⁰ cd / cm ² or less. It said difference is more 15 cd / cm ² or less, further 10 cd / cm ² or less, more preferably at 5 cd / cm ² or less. The smaller the difference, the smaller the light leakage.

  In the laminated combined optical films (11) and (12), a retardation plate can be selected and used as the optical film used for the combined optical film of each layer.

As described above, using a retardation plate as a combination type optical film of each layer, the laminated combination type retardation plate is disposed on both sides of the laminated combination retardation plate adjacent to the liquid crystal cell on the backlight side. A liquid crystal panel in which polarizing plates (not combined) are arranged in crossed Nicols, and arranged such that the absorption axis of the polarizing plate on the backlight side is substantially parallel to the slow axis of the laminated combination phase difference plate The difference between the center luminance A (cd / cm ² ) and the peripheral luminance B (cd / cm ² ) of the butt portion of the laminated combination type retardation plate (center luminance A−peripheral luminance B) measured for the liquid crystal panel used. ) Is preferably ²⁰ cd / cm ² or less. The difference is more 15 cd / cm ² or less, further 10 cd / cm ² or less, more preferably at 5 cd / cm ² or less. The smaller the difference, the smaller the light leakage.

  In the laminated combined optical films (11) and (12), an easily peelable protective film is attached to a plurality of optical films forming a combined optical film on the front surface and / or the back surface. The adhesive tape is stuck on the adjacent said protective film corresponding to the butting | matching part in a type | mold optical film, and what the said protective films have joined can be used.

  When attaching an easily peelable protective film to the front or back surface of the plurality of optical films, the protective film is peeled off by attaching an adhesive tape to the protective films and joining the protective films together. Sometimes, the adjacent protective films can be peeled at once, and the troublesome peeling work can be simplified.

  The present invention also relates to an image display device using the combined optical film or the laminated combined optical film.

  The combination optical film (1), (2), (3), (4), (5), (6), or the laminated combination optical film (11), (12) is a film in the gap between the butted portions. When this is applied to a liquid crystal display device or the like, light leakage due to irradiation light from the back surface can be suppressed without impairing the surface appearance.

  In addition, the combination type optical film is made of the plurality of optical films, and an optical film having a desired size can be made by using an optical film that has been used in the past. It can also be suitably applied to a film. In addition, the combination type optical film can be easily transported because each optical film can be transported apart. Furthermore, the surplus part (optical film) which has become a waste product with an odd size can be reused by the matching technique.

  Refer to the drawings for the combined optical films (1), (2), (3), (4), (5), (6) and the laminated combined optical films (11), (12) of the present invention. While explaining.

  1 to 9 show a combination type optical film in which at least one end surfaces of a plurality of optical films are abutted with each other, the abutting end surfaces substantially coincide with each other, and the abutting end surfaces are the front and back surfaces of the optical film. On the other hand, the combination type optical film (1) having at least a portion which is not perpendicular is exemplified. The butted end surfaces are butted so as not to have a continuous gap from the front surface to the back surface in the normal direction of the optical film. FIGS. 1-9 is an example at the time of combining two optical films A. FIG. In addition, the surface and the back surface of the optical film are not distinguished, and either side may be the surface or the back surface.

  In the combined optical film (1), the abutting end faces x have shapes that match each other. Further, the butt end face x is not particularly limited as long as it has a portion that is not perpendicular to the front and back surfaces of the optical film A. For example, the shape of the butt end face x is shown in FIGS. 1 and 2 show a case where the shape of the butted end face x is inclined from the front surface to the back surface of the optical film A. FIG. FIG. 3 shows a case where concave and convex molds are combined. FIG. 4 shows a case where key types are combined. FIG. 5 shows a case where V-shapes are combined. FIG. 6 shows a case where a part of the optical film A is inclined from the front surface to the back surface, and a part thereof is vertical. FIG. 7 shows a combination of semicircular shapes. FIG. 8 shows a case where circular inclined types are combined. FIG. 9 shows a case where wave forms are combined.

  In the combined optical film (1), the shape of the butted end face x may be inclined from the front surface to the back surface of the optical film A as shown in FIGS. preferable. In the abutting end face x having such a plane inclination, the inclination angle θ formed between the end face x and the normal direction with respect to the optical film A varies depending on the type and thickness of the optical film, and can be designed as appropriate. As described above, when the inclination angle of the butt end face is θ (°), the average gap between the films in the butt portion is t (μm), and the thickness of the optical film is d (μm), t ≦ d × tan θ, Is preferably satisfied. Moreover, it is preferable that 1 ° ≦ θ ≦ 60 °. For example, when the optical film is a polarizer and the accuracy of the butt gap is 5 μm, when the thickness of the polarizer is 10 μm, the inclination angle θ is 30 ° or more, when the thickness is 20 μm, θ is 15 ° or more, and the thickness is 30 μm. θ is preferably 10 ° or more, and θ is preferably 6 ° or more when the thickness is 50 μm. In addition, the gap t is usually preferably 20 μm or less and desirably no gap so that the butt end face does not have a continuous gap from the front surface to the back surface in the normal direction of the optical film. It is. In order to eliminate the gap, it is preferable to accurately process the butt end face x by a method such as cutting or polishing.

  Usually, the same optical film A is used. In each figure, the optical films A shown as a pair on the left and right are preferably the same.

  Examples of the optical film A include various types. In FIG. 1, one layer is used as the optical film A. The optical film A may be a single layer or a laminate of two or more layers. FIG. 2 shows an optical film A in which both surfaces of an optical film a1 are laminated with an optical film a2. For example, in FIG. 2, if it is a1: polarizer and a2: polarizer protective film, the optical film A is a polarizing plate in which protective films are laminated on both sides of the polarizer. The lamination in FIG. 2 may use an adhesive or an adhesive, but is omitted in FIG. Examples of the optical film include a retardation plate, an optical compensation film, a brightness enhancement film, and the like in addition to those exemplified above. These aspects are the same in the optical film A shown in other figures.

  FIG. 10 shows a combined optical film formed by abutting at least one end face of a plurality of optical films with each other, wherein the abutting end face is bonded with a bonding agent having substantially the same refractive index as that of the optical film. The combination type optical film (2) to be illustrated is illustrated. FIG. 10 shows an example in which two optical films A are combined.

  In FIG. 10, the butted end surface x is bonded with a bonding agent S having substantially the same refractive index as that of the optical film A. As the bonding agent, generally known adhesives and pressure-sensitive adhesives are used. At this time, if an adhesive is used, re-peeling is possible, so reassembly is easy and it is preferably used. The difference in refractive index between the optical film A and the bonding agent S is preferably 0.03 or less, and more preferably 0.02 or less. The refractive index is a value measured with an Abbe refractometer at a wavelength of 589.3 nm.

  FIG. 11 is a combination type optical film in which at least one end face of a plurality of optical films is abutted against each other, and the abutting end faces are joined by dissolution and solidification with an organic solvent capable of dissolving the optical film. A combination type optical film (3) is illustrated. FIG. 11 shows a combined optical film in which at least one end surface of a plurality of optical films is butted against each other, and the butted end surfaces are bonded by heat fusion (4 ). FIG. 11 shows an example in which two optical films A are combined.

  In FIG. 11, the butt end face x is joined and integrated by melting, solidifying, or melting of the optical film A.

  10 or 11, the butt end face x can be the one illustrated in FIGS. 1 to 9.

  FIG. 12A is an illustration of a combined optical film (5) using a plurality of optical films having a diffusion layer on the surface. FIG. 13A is an illustration of a combined optical film (6) having a diffusion layer on the surface. 12A and 13A, the butt end surface x is perpendicular to the optical film A, but the structure of the butt end surface x is the combination optical film (1), (2), ( 3) and (4). FIGS. 12B and 13B illustrate the case where the diffusion layer D is provided on the surface of the combination optical film (1) shown in FIG. The diffusion layer may be provided on the back surface or on both surfaces. Further, instead of the diffusion layer D or together with the diffusion layer D, an optical film A ′ can be used. The optical film A ′ may be provided by a plurality of optical films A, or may be provided as a single piece on a combined optical film in which end faces x of the plurality of optical films A are abutted. FIG. 13C shows an example in which a single optical film A ′ and a diffusion layer D are further provided on a combined optical film in which end faces x of a plurality of optical films A are abutted. The optical film A ′ can be the same as the optical film A.

  FIG. 14 shows that an easily peelable protective film is attached to the front and back surfaces of a plurality of optical films in a combined optical film, and the adjacent protective films on the adjacent protective films corresponding to the butted portions in the combined optical film. Is an example in which an adhesive tape is affixed to the protective film and the protective films are joined together. In FIG. 14, on the surface of the optical film A, an easily peelable protective film L1 (a laminate of an easily peelable adhesive layer on a base film) is laminated. On the other hand, an easily peelable protective film L2 (separator) for the pressure-sensitive adhesive layer P is laminated on the back surface of the optical film A. The protective film L2 (separator) is peeled off at the adhesive interface with the pressure-sensitive adhesive layer P, whereas the protective film L1 is usually a laminate of an easily peelable pressure-sensitive adhesive layer on a base film. The base film is peeled and removed together with the adhesive layer. In the case where the optical film A is laminated with the pressure-sensitive adhesive layer P and processed into a plane inclination of the butt end face x, the optical film with the pressure-sensitive adhesive layer including the pressure-sensitive adhesive layer P is t ≦ d × tan θ, It is preferable to satisfy θ ≦ θ ≦ 60 °.

  Further, the protective films L1 and L2 of each optical film A are joined together by an adhesive tape T. In FIG. 14, the protective films L <b> 1 and L <b> 2 are provided on both sides of the optical film A, but these may be either one or the same on both sides. FIG. 15 shows an example in which two optical films A are combined vertically and horizontally (four in total). In FIGS. 14 and 15, the adhesive tape T is provided at a part of the joint between the protective films L1 and L2, but may be provided at all.

  In addition, in FIG. 14, FIG. 15, although the case of the combination type optical film (1) shown in FIG. 1 was illustrated, the combination type optical film (1) other than shown in FIG. 1, a combination type optical film (2), The same applies to (3), (4), (5), and (6).

  FIG. 16 is an example of a laminated combined optical film (11) in which at least two layers of the combined optical film are stacked. FIG. 16 illustrates the case where two of the combination type optical films (1) shown in FIG. 1 are laminated. In addition to this, the combination type optical film (1) other than that shown in FIG. The same applies to the optical films (2), (3), (4), (5) and (6). Moreover, these can be combined.

  FIG. 17 is a laminated combined optical film obtained by laminating a plurality of combined optical films obtained by abutting at least one end face of a plurality of optical films with each other. It is an example of the lamination | stacking combination type | mold optical film (12) laminated | stacked so that the butting | matching part might not overlap in the normal line direction with respect to a combination type | mold optical film.

  In the laminated combined optical film (12), a combined optical film of the optical film A1 and the optical film A1 and a combined optical film of the optical film A2 and the optical film A2 are laminated. Each butted end face x is perpendicular to each optical film A1 or A2, but each butted portion is arranged so as not to overlap.

  In FIGS. 16 and 17, the same optical films A1 and A2 are usually used in combination. In each figure, the optical films A1 and A2 shown as a pair on the left and right are preferably the same. On the other hand, different types of optical films A1 and A2 can be used. For example, if the optical film A1 is a polarizer and the optical film A2 is a protective film for the polarizer, the laminate can be a polarizing plate. In addition, a polarizing plate can be used for both of the optical films A1 and A2. Further, the optical film A1 can be a polarizing plate, and the optical film A2 can be a retardation plate. The lamination in FIGS. 16 and 17 may be omitted, although an adhesive or a pressure-sensitive adhesive may be used. Examples of the optical films A1 and A2 include an optical compensation film and a brightness enhancement film in addition to the above-described examples. These aspects are the same in the optical films A1 and A2 shown in other figures.

  FIG. 18 shows an example of a case where a plurality of optical films A1 forming a combined optical film on a surface of a laminated combined optical film have a diffusion layer D on the surface thereof. FIG. 19A is an example when a diffusion layer D is provided on the surface of a laminated combined optical film. In FIG. 18 and FIG. 19A, the diffusion layer D is provided on the surface of the laminated combined optical film shown in FIG. 17, but the diffusion layer D may be provided on the back surface or on both surfaces. Also good. Moreover, you may provide the diffusion layer D in the intermediate surface between the combination type optical film by optical film A1, and the combination type optical film by optical film A2. Further, instead of the diffusion layer D or together with the diffusion layer D, an optical film A ′ can be used. The optical film A ′ may be provided by a plurality of optical films A1 or A2, and is provided as a single piece on a combined optical film in which the end faces x of the plurality of optical films A1 or A2 are abutted. Also good. FIG. 19B shows a combination type optical film in which the end faces x of a plurality of optical films A1 shown in FIG. 17 are abutted with one optical film A ′ on both sides, and a plurality of optical films A2. This is an example in which one optical film A ′ provided on both sides of a combination type optical film in which the end faces x are laminated is laminated and a diffusion layer D is provided on the inner surface thereof. The optical film A ′ can be the same as the optical film A. Further, the structure of the butted end face x of each layer in FIGS. 18, 19A, and 19B is as shown in the combination optical films (1), (2), (3), and (4). it can.

  FIG. 20 shows a laminated combined optical film. A plurality of optical films forming a combined optical film on the front surface and the back surface are provided with easily peelable protective films, and butt end faces in the combined optical film Is an example in which an adhesive tape is stuck on the adjacent protective films and the protective films are connected to each other. In FIG. 20, on the surface of the optical film A1, an easily peelable protective film L1 (a laminate of an easily peelable adhesive layer on a base film) is laminated. On the other hand, an easily peelable protective film L2 (separator) for the pressure-sensitive adhesive layer P is laminated on the back surface of the optical film A2. In addition, the protective films L1 and L2 of the optical films A1 and A2 are joined together by an adhesive tape T. In FIG. 20, the optical films A1 and A2 have the protective films L1 and L2, respectively, but these may be either one or the same on both sides. In FIG. 20, the adhesive tape T is provided at a part of the joint between the protective films L1 and L2, but may be provided at all.

  In addition, in FIG. 20, although the case of a lamination | stacking combination type | mold optical film (12) is illustrated, it is not restrict | limited to this.

  Moreover, in FIGS. 16-20, although the case where two optical films A1 and A2 which form a combination type | mold optical film are used is illustrated, two optical films A1 and A2 are each longitudinally and laterally (total four sheets) ) Can be combined. In this case, the respective butted portions of each combination type optical film are arranged so as not to overlap each other. However, these butted portions may be arranged so as not to overlap in a line shape, and may be overlapped in terms of dots.

  Optical films used for the combination type optical films (1), (2), (3), (4), (5), (6) and the laminated combination type optical films (11), (12) of the present invention below. explain.

  As an optical film, what is used for formation of image display apparatuses, such as a liquid crystal display device, is used, and the kind in particular is not restrict | limited. For example, the optical film includes a polarizing plate. A polarizing plate having a transparent protective film on one or both sides of a polarizer is generally used. Moreover, a polarizer and a transparent protective film can each be used as an optical film separately.

  The polarizer is not particularly limited, and various types can be used. Examples of polarizers include dichroic iodine and dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be prepared by, for example, dying polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched even in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As a material for forming the transparent protective film provided on one side or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) -Based polymer, polycarbonate-based polymer and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of polymers that form the transparent protective film. The transparent protective film can also be formed as a cured layer of thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylurethane, epoxy, and silicone.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing a thermoplastic resin having unsubstituted phenyl and a nitrile group. A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used.

  Although the thickness of a protective film can be determined suitably, generally it is about 1-500 micrometers from points, such as workability | operativity, such as intensity | strength and handleability, and thin film property. In particular, 5 to 200 μm is preferable.

  Moreover, it is preferable that a protective film has as little color as possible. Therefore, Rth = (nx−nz) · d (where nx is the refractive index in the slow axis direction in the film plane, nz is the refractive index in the film thickness direction, and d is the film thickness). A protective film having a direction retardation of −90 nm to +75 nm is preferably used. By using a film having a thickness direction retardation value (Rth) of −90 nm to +75 nm, coloring (optical coloring) of the polarizing plate caused by the protective film can be almost eliminated. The thickness direction retardation (Rth) is more preferably -80 nm to +60 nm, and particularly preferably -70 nm to +45 nm.

  As the protective film, a cellulose polymer such as triacetyl cellulose is preferable from the viewpoints of polarization characteristics and durability. A triacetyl cellulose film is particularly preferable. In addition, when providing a protective film on both sides of a polarizer, the protective film which consists of the same polymer material may be used by the front and back, and the protective film which consists of a different polymer material etc. may be used.

  The polarizer and the protective film are usually in close contact with each other through an aqueous adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester.

  The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a treatment for the purpose of hard coat layer, antireflection treatment, sticking prevention, diffusion or antiglare.

  The hard coat treatment is applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone is used. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. Further, the sticking prevention treatment is performed for the purpose of preventing adhesion between adjacent layers of other members.

  Anti-glare treatment is applied for the purpose of preventing external light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by sandblasting or embossing. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a method or a compounding method of transparent fine particles. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 to 50 μm. In some cases, transparent fine particles such as inorganic fine particles and organic fine particles (including beads) made of a crosslinked or uncrosslinked polymer are used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, antisticking layer, diffusion layer, antiglare layer, and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film as an optical layer.

  In addition, as an optical film, for example, it is used for forming a liquid crystal display device such as a reflection plate, an anti-transmission plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), a viewing angle compensation film, and a brightness enhancement film. And an optical layer that may be formed. These can be used alone as an optical film, or can be laminated on the polarizing plate for practical use and used as one layer or two or more layers.

  In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate is further laminated with a reflecting plate or a semi-transmissive reflecting plate, an elliptical polarizing plate or a circular polarizing plate in which a retardation plate is further laminated on a polarizing plate, a polarizing plate A wide viewing angle polarizing plate in which a viewing angle compensation film is further laminated on a plate, or a polarizing plate in which a brightness enhancement film is further laminated on a polarizing plate is preferable.

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. In addition, the transparent protective film may contain fine particles to form a surface fine concavo-convex structure, and a reflective layer having a fine concavo-convex structure thereon. The reflective layer having the fine concavo-convex structure has an advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance and to suppress unevenness in brightness and darkness. Moreover, the protective film containing fine particles also has an advantage that incident light and its reflected light are diffused when passing through it and light and dark unevenness can be further suppressed. The reflective layer of the fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film is formed by, for example, applying metal to the surface of the transparent protective layer by an appropriate method such as a vacuum deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of attaching directly to the screen.

  Instead of the method of directly applying the reflecting plate to the transparent protective film of the polarizing plate, the reflecting plate can be used as a reflecting sheet provided with a reflecting layer on an appropriate film according to the transparent film. Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate or the like is used to prevent the reflectance from being lowered due to oxidation, and thus to maintain the initial reflectance for a long time. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device of a type that displays an image using a built-in power source such as a backlight built in the back side of the transflective polarizing plate can be formed. In other words, the transflective polarizing plate can be used to form liquid crystal display devices that can save energy when using a light source such as a backlight in a bright atmosphere and can be used with a built-in power supply even in a relatively dark atmosphere. It is.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. A phase difference plate or the like is used when changing linearly polarized light to elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called quarter-wave plate (also referred to as a λ / 4 plate) is used as a retardation plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A half-wave plate (also referred to as a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function.

  Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by a film. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 μm.

  Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymer, norbornene resin, or binary, ternary copolymers, graft copolymers, Examples include blends. These polymer materials become an oriented product (stretched film) by stretching or the like.

  Examples of the liquid crystal polymer include various main chain types and side chain types in which a conjugated linear atomic group (mesogen) imparting liquid crystal alignment is introduced into the main chain or side chain of the polymer. . Specific examples of the main chain type liquid crystal polymer include a nematic alignment polyester liquid crystal polymer, a discotic polymer, and a cholesteric polymer having a structure in which a mesogen group is bonded at a spacer portion that imparts flexibility. Specific examples of the side chain type liquid crystal polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a nematic alignment-providing para-substitution through a spacer portion composed of a conjugated atomic group as a side chain. Examples thereof include those having a mesogenic part composed of a cyclic compound unit. These liquid crystal polymers are prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment treatment surface such as a surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or an oblique deposition of silicon oxide. This is done by developing and heat treatment.

  The retardation plate may have an appropriate retardation according to the purpose of use, such as those for the purpose of compensating for various wavelength plates or birefringence of liquid crystal layers and compensation of viewing angle, etc. It may be one in which retardation plates are stacked and optical characteristics such as retardation are controlled.

  The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially laminating them sequentially in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflective) polarizing plate and a retardation plate. An optical film such as a polarizing plate has an advantage that it can improve the production efficiency of a liquid crystal display device and the like because of excellent quality stability and lamination workability.

  The viewing angle compensation film is a film for widening the viewing angle so that an image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction rather than perpendicular to the screen. As such a viewing angle compensation phase difference plate, for example, a phase difference plate, an alignment film such as a liquid crystal polymer, or an alignment layer such as a liquid crystal polymer supported on a transparent substrate is used. A normal retardation plate uses a birefringent polymer film uniaxially stretched in the plane direction, whereas a retardation plate used as a viewing angle compensation film stretches biaxially in the plane direction. Birefringent polymer film, biaxially stretched film such as polymer with birefringence with a controlled refractive index in the thickness direction that is uniaxially stretched in the plane direction and stretched in the thickness direction, etc. Used. Examples of the inclined alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and shrinking the polymer film under the action of the contraction force by heating, and a film obtained by obliquely aligning a liquid crystal polymer. can give. The raw material polymer for the phase difference plate is the same as the polymer described in the previous phase difference plate, preventing coloration due to a change in the viewing angle based on the phase difference by the liquid crystal cell and expanding the viewing angle for good visual recognition. An appropriate one for the purpose can be used.

  In addition, from the viewpoint of achieving a wide viewing angle with good visibility, an optical compensation position in which an alignment layer of a liquid crystal polymer, particularly an optically anisotropic layer composed of a tilted alignment layer of a discotic liquid crystal polymer, is supported by a triacetyl cellulose film. A phase difference plate can be preferably used.

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer or the like provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. Luminance can be improved by increasing the amount of light transmitted through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to be absorbed by the polarizer. That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and accordingly, the amount of light that can be used for liquid crystal image display or the like is reduced and the image becomes dark. The brightness enhancement film reflects light that has a polarization direction that is absorbed by the polarizer without being incident on the polarizer, and is reflected by the brightness enhancement film, and then inverted through a reflective layer or the like provided behind the brightness enhancement film. The brightness enhancement film transmits only the polarized light in which the polarization direction of the light reflected and inverted between the two is allowed to pass through the polarizer. Since the light is supplied to the polarizer, light such as a backlight can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

  A diffusion plate may be provided between the brightness enhancement film and the reflective layer. The polarized light reflected by the brightness enhancement film is directed to the reflective layer or the like, but the installed diffuser plate uniformly diffuses the light passing therethrough and simultaneously cancels the polarized state and becomes a non-polarized state. That is, the light in the natural light state is directed toward the reflection layer or the like, reflected through the reflection layer or the like, and again passes through the diffusion plate and reenters the brightness enhancement film. In this way, by providing a diffuser plate that returns polarized light to the original natural light between the brightness enhancement film and the reflective layer, the brightness of the display screen is maintained, and at the same time, the brightness of the display screen is reduced and uniform. Can provide a bright screen. By providing such a diffuser plate, it is considered that the first incident light has a moderate increase in the number of repetitions of reflection, and in combination with the diffusion function of the diffuser plate, a uniform bright display screen can be provided.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of dielectric material or a multilayer laminate of thin film films having different refractive index anisotropies. Such as an alignment film of a cholesteric liquid crystal polymer or an alignment liquid crystal layer supported on a film substrate, which reflects either left-handed or right-handed circularly polarized light and transmits other light. Appropriate things, such as a thing, can be used.

  Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis as described above, the transmitted light is incident on the polarizing plate with the polarization axis aligned as it is, thereby efficiently transmitting while suppressing absorption loss due to the polarizing plate. Can be made. On the other hand, in a brightness enhancement film of a type that transmits circularly polarized light such as a cholesteric liquid crystal layer, it can be incident on a polarizer as it is, but from the point of suppressing absorption loss, the circularly polarized light is converted into linearly polarized light through a retardation plate. It is preferably incident on the polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate at a wide wavelength in the visible light region or the like exhibits, for example, a retardation plate that functions as a quarter-wave plate for light-colored light having a wavelength of 550 nm and other retardation characteristics. It can be obtained by a method in which a phase difference layer, for example, a phase difference layer that functions as a half-wave plate is superimposed. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.

  In addition, a cholesteric liquid crystal layer having a reflection structure that reflects circularly polarized light in a wide wavelength range such as a visible light range can be obtained by combining two or more layers with different reflection wavelengths to form an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Further, the polarizing plate may be formed by laminating a polarizing plate and two or more optical layers as in the above-described polarization separation type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-described reflective polarizing plate or semi-transmissive polarizing plate and a retardation plate are combined may be used.

  An optical film in which the optical layer is laminated on a polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of a liquid crystal display device or the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target phase difference characteristic.

  An adhesive layer for adhering to other members such as a liquid crystal cell may be provided on one side or both sides of the optical film. Such an adhesive layer can also be used for lamination of optical films, and a separator can be provided on the adhesive layer. 14, 15, and 20, an easily peelable protective film (separator) L <b> 2 is provided for the adhesive layer P.

  The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited. For example, an acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer is appropriately selected. Can be used. In particular, those having excellent optical transparency such as an acrylic pressure-sensitive adhesive, exhibiting appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and being excellent in weather resistance, heat resistance and the like can be preferably used.

  In addition to the above, in terms of prevention of foaming and peeling phenomena due to moisture absorption, deterioration of optical properties and liquid crystal cell warpage due to differences in thermal expansion, etc., as well as formability of liquid crystal display devices with high quality and excellent durability An adhesive layer having a low moisture absorption rate and excellent heat resistance is preferred.

  The adhesive layer is, for example, natural or synthetic resins, in particular, tackifier resins, fillers or pigments made of glass fibers, glass beads, metal powders, other inorganic powders, colorants, antioxidants, etc. It may contain an additive to be added to the adhesive layer. Moreover, the adhesion layer etc. which contain microparticles | fine-particles and show light diffusibility may be sufficient.

  Attachment of the adhesive layer to one side or both sides of the optical film can be performed by an appropriate method. For example, a pressure sensitive adhesive solution of about 10 to 40% by weight in which a base polymer or a composition thereof is dissolved or dispersed in a solvent composed of a suitable solvent alone or a mixture such as toluene and ethyl acetate is prepared. A method in which it is directly attached on a polarizing plate or an optical film by an appropriate development method such as a casting method or a coating method, or an adhesive layer is formed on a separator according to the above, and this is applied to a polarizing plate or an optical film. The method of moving up is mentioned.

  The adhesive layer can also be provided on one or both sides of the optical film as a superimposed layer of different compositions or types. Moreover, when providing in both surfaces, it can also be set as the adhesion layers of a different composition, a kind, thickness, etc. in the front and back of a polarizing plate or an optical film. The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to the purpose of use and adhesive force, and is generally 1 to 500 μm, preferably 5 to 200 μm, particularly preferably 10 to 100 μm.

  On the exposed surface of the adhesive layer, a separator is temporarily attached and covered for the purpose of preventing contamination until it is put to practical use. Thereby, it can prevent contacting an adhesion layer in the usual handling state. As the separator, except for the above thickness conditions, for example, a suitable thin leaf body such as a plastic film, rubber sheet, paper, cloth, non-woven fabric, net, foam sheet, metal foil, laminate thereof, and the like, silicone type or Appropriate ones according to the prior art, such as those coated with an appropriate release agent such as a long mirror alkyl type, fluorine type or molybdenum sulfide, can be used.

  The optical film may be provided with an easily peelable protective film in order to protect the optical film itself. In FIG. 14, FIG. 15, and FIG. 20, an easily peelable protective film L1 is provided.

  Although the protective film can be formed only on the base film, it is generally formed so that an adhesive layer is provided on the base film and the base film can be peeled from the optical film together with the adhesive layer.

  In the present invention, each layer such as an optical film and an adhesive layer is treated with an ultraviolet absorber such as a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex compound. It may be one having an ultraviolet absorbing ability by such a method.

  The production methods of the combined optical films (1), (2), (3), (4), (5), (6) and the laminated combined optical films (11), (12) of the present invention will be described below. .

  When manufacturing the combination type optical film (1), (2), (3), (4), (5), (6) of the present invention, the combination type optical film is combined according to the size of the combination type optical film to be manufactured. Adjust the size of each optical film. The number of optical films to be combined is not particularly limited. The size of the combined optical film to be manufactured is not limited, but is particularly effective in the case of a large size of 65 inches or more (or 800 mm or more in length and 1350 mm or more in width). On the other hand, even when the combined optical film to be manufactured is small, there is an effect that individual optical films can be easily transported and conveyed.

  In the production of the combined optical film (1) of the present invention, the end faces of the optical films to be abutted are substantially coincident with each other and have at least portions that are not perpendicular to the front and back surfaces of the optical film. Process into shape. For example, when the end face of the optical film is inclined as shown in FIG. 1, a plurality of optical films are stacked, and the end face of the optical film is processed at a desired angle by a cutting machine or the like. Can be processed.

  In the combined optical film (1), the end faces of the optical film processed into the above shape are butted together. At the abutting portion on the front surface or the back surface of the optical film, there is no continuous gap from the front surface to the back surface in the normal direction of the optical film.

  In the production of the combined optical film (2) of the present invention, the end faces of the optical film are butted together and bonded to the gap (about 0 to 20 μm) of the butted portion with a bonding agent having substantially the same refractive index as the optical film. To do. The bonding agent is appropriately determined according to the type of the optical film. For example, various types such as acrylic, epoxy, and polyester can be used. The bonding agent may be either a releasable adhesive or a non-removable adhesive, but the adhesive can be recombined and has the advantage of being able to be compact during transportation and storage.

  In the production of the combined optical film (3) of the present invention, the end faces of the optical film are butted together, and an organic solvent that can dissolve the optical film is poured into the gap (about 0 to 20 μm) of the butted portion. The butt portion is joined by dissolving the optical film and then drying and solidifying. The organic solvent is appropriately determined according to the type of optical film. For example, when triacetyl cellulose is used as the optical film (polarizer protective film), examples of the organic solvent include halogen solvents, ester solvents, and ketone solvents. Of these, methylene chloride and acetyl acetate are excellent in solubility. When a norbornene resin is used as the optical film (protective film for the polarizer), a hydrocarbon solvent can be exemplified as the organic solvent. Of these, hexane, heptane, octane and the like are good in solubility.

  In the production of the combined optical film (4) of the present invention, the end faces of the optical film are butted against each other, and the gap (about 0 to 20 μm) of the butted portion is joined by thermal fusion. The heat sealing conditions are appropriately determined according to the type of optical film. For example, in the case of a triacetyl cellulose film, it can be fused at a temperature of 160 ° C. or higher.

  In the production of the combined optical film (5) of the present invention, the end faces of the optical film having the diffusion layer are brought into contact with each other. The gap between the butted portions is preferably about 0 to 20 μm.

  In the production of the combined optical film (6) of the present invention, the end surfaces of the optical films are butted against each other, and then a diffusion layer is provided. The gap between the butted portions is preferably about 0 to 20 μm.

  The laminated combined optical film (11) of the present invention is a method for sequentially forming combined optical films (1), (2), (3), (4), (5), and (6) that form each layer. Alternatively, it is prepared by laminating separately prepared combination type optical films (1), (2), (3), (4), (5), (6).

  The laminated combined optical film (12) of the present invention is also prepared by sequentially forming a combined optical film for forming each layer or by laminating separately prepared combined optical films. The mold optical film is made so that the butted portions do not overlap. Although the interval between the butted portions depends on the size of the optical film, it is usually preferable to provide an interval of 100 mm or more, more preferably 200 mm or more.

  The diffusion layer provided on one side or both sides of the combination type optical films (5) and (6) or the laminated combination type optical films (11) and (12) of the present invention is the same method as the above-described example diffusion layer or antiglare layer. Can be provided. The diffusion layer can be provided as a diffusion adhesive material. For example, a fine particle dispersion type diffusing material as disclosed in JP 2000-347006 A and JP 2000-347007 A is preferably used. The thickness of the diffusion layer is not particularly limited, and it is preferable that the diffusion layer can diffuse light leakage without causing a problem in the optical characteristics of the optical film. The haze of the diffusion layer is preferably 0 to 90%, more preferably 60 to 90%.

  The combined optical films (1), (2), (3), (4), (5), (6) and the laminated combined optical films (11), (12) of the present invention are shown in FIGS. When the adhesive tape used in the embodiment as shown in FIG. 20 is used, the adhesive tape to be bonded onto the protective film can be used without particular limitation as long as it has an adhesive force that allows the protective films to be joined and peeled and removed together.

  The combined optical film and laminated combined optical film of the present invention can be preferably used for forming various image display devices such as liquid crystal display devices. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell and the combined optical film or laminated combined optical film, and an illumination system as necessary, and incorporating a drive circuit. In the present invention, there is no particular limitation except that the combination type optical film or the laminated combination type optical film is used, and it can conform to the conventional one. As the liquid crystal cell, an arbitrary type such as an arbitrary type such as a TN type, an STN type, or a π type can be used.

  Appropriate liquid crystal display devices such as a liquid crystal display device in which the combination type optical film or the laminated combination type optical film is disposed on one side or both sides of a liquid crystal cell, and a backlight or reflector used in an illumination system may be formed. it can. When the combination type optical film or the laminated combination type optical film is provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. The combined optical film or laminated combined optical film (polarizing plate etc.) of the present invention can also be applied to an organic EL display device. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a stacked body of such a light emitting layer and an electron injection layer made of a perylene derivative, or a stacked body of these hole injection layer, light emitting layer, and electron injection layer is known. It has been.

  In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the phosphor material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

  Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .

  That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light particularly when the phase difference plate is a quarter wavelength plate and the angle formed by the polarization direction of the polarizing plate and the phase difference plate is π / 4. .

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

  Hereinafter, the present invention will be described more specifically by describing examples. However, the present invention is not limited to these examples.

Example 1
As the polarizing plate, a polyvinyl alcohol polarizer (thickness: 25 μm) and a protective film made of triacetylcellulose (40 μm on one side and 80 μm on both sides) bonded with a polyvinyl alcohol adhesive were used.

  One end face (vertical side) of the polarizing plate (vertical 400 mm, horizontal 300 mm) was processed so that an inclination angle formed between the processed end face and the normal direction to the polarizing plate was 15 °. The processed end faces were butted to make a combined polarizing plate. The gap between the butted portions was 10 μm, but the butted portions were butted in the normal direction of the polarizing plate so as not to have a continuous gap from the front surface to the back surface.

Example 2
In Example 1, the polarizing plate was used except that one end face (longitudinal side) was processed so that the inclination angle formed between the processing end face and the normal direction to the polarizing plate was 30 °. A combination polarizing plate was prepared in the same manner as in Example 1.

Example 3
On one side of the polarizing plate described in Example 1, a pressure-sensitive adhesive having a diffusion function having a haze value of 80% mixed with fine particles of silicone resin was applied to form a diffusion layer (thickness 25 μm).

  One end face (longitudinal side) of the polarizing plate with the diffusion layer was processed from the side of the diffusion layer so that the inclination angle formed between the processed end face and the normal direction to the polarizing plate was 15 °. On the other hand, for the polarizing plate with the same type of diffusion layer, the polarizing plate has an inclination angle of 15 ° between the processed end surface and the normal direction with respect to the polarizing plate so that the shape of the butt end surface and the shape of each other substantially coincide with each other. Processed from the side. These processed end faces were brought into contact with each other to produce a combined polarizing plate. The gap between the butted portions was 10 μm, but the butted portions were butted in the normal direction of the polarizing plate so as not to have a continuous gap from the front surface to the back surface.

Example 4
After processing the polarizing plate created in Example 1 in the same manner as in Example 1, the processed end faces were butted together. Next, methylene chloride was blended into the gap between the butted portions with a brush to dissolve the triacetyl cellulose, and then solidified by drying and bonded to form a combined polarizing plate.

Example 5
On one side of the polarizing plate described in Example 1, a pressure-sensitive adhesive having a diffusion function having a haze value of 80% mixed with fine particles of silicone resin was applied to form a diffusion layer (thickness 25 μm).

  One end face (vertical side) of the polarizing plate with the diffusion layer was processed so that the end face was perpendicular to the polarizing plate. These processed end faces were butted together to create a combined polarizing plate. The gap between the butted portions was 10 μm.

Example 6
One end face (vertical side) of the polarizing plate prepared in Example 1 was processed so that the end face was perpendicular to the polarizing plate. These processed end faces were butted together. Next, methylene chloride was blended into the gap between the butted portions with a brush to dissolve the triacetyl cellulose, and then solidified by drying and bonded to form a combined polarizing plate.

Example 7
One end face (vertical side) of the polarizing plate prepared in Example 1 was processed so that the end face was perpendicular to the polarizing plate. These processed end faces were butted so that the gap between the butted portions was 10 μm. Next, a cyanoacrylate adhesive (Aron Alpha, manufactured by Toa Gosei Co., Ltd., the refractive index of the adhesive is 1.52, and the refractive index 1.49 of the polarizing plate (triacetyl cellulose part) The difference was 0.03), and the adhesive was solidified and joined to create a combined polarizing plate. In the cyanoacrylate adhesive, triacetyl cellulose is partially dissolved, and the portion is dissolved and solidified.

Example 8
One end face (vertical side) of the polarizing plate prepared in Example 1 was processed so that the end face was perpendicular to the polarizing plate. These processed end faces were butted so that the gap between the butted portions was 10 μm. Separately, butting was performed in the same manner as described above so that the gap between the butting portions was 10 μm. These two combination-type polarizing plates were overlapped so that the butted portions did not overlap each other (the interval between the butted portions was 100 mm), thereby producing a laminated combined polarizing plate.

Example 9
As the retardation plate, a uniaxially stretched film (thickness 80 μm, front retardation 140 nm) of a thermoplastic saturated norbornene resin (Arton, manufactured by JSR) was used. On one side of the retardation plate, an acrylic adhesive layer having a thickness of 25 μm was provided to obtain a retardation plate with an adhesive layer.

  One end face (vertical side) of the above-mentioned phase difference plate with an adhesive layer (vertical 400 mm, horizontal 300 mm) was processed so that the inclination angle formed between the processed end surface and the normal direction to the retardation plate was 15 °. The processed end faces were butted together to produce a retardation plate with a combined pressure-sensitive adhesive layer. The gap of the butted portion was 10 μm, but the abutting portion was abutted so as not to have a continuous gap from the front surface to the back surface in the normal direction of the phase difference plate with the adhesive layer.

Comparative Example 1
One end face (vertical side) of the polarizing plate prepared in Example 1 was processed so that the end face was perpendicular to the polarizing plate. A combination type polarizing plate was prepared by abutting so that the clearance between these processed end faces was 10 μm.

Comparative Example 2
In Example 1, a combined polarizing plate was produced in the same manner as in Example 1 except that the polarizing plates were butted so that the gap between the butted portions was 50 μm.

Comparative Example 3
In Example 9, a combined phase difference plate was prepared in the same manner as in Example 1 except that the phase difference plate with the pressure-sensitive adhesive layer was abutted so that the gap between the abutting portions was 50 μm.

(Evaluation)
The following evaluation was performed about the combination type polarizing plate (including the case of lamination | stacking) or the phase difference plate with a combination type adhesive layer obtained by the Example and the comparative example. The results are shown in Table 1.

(Combination type polarizing plate)
A polarizing plate (NPF-SEG1224DU: NITTO DENKO (NITTO DENKO) Manufactured), and a combination type polarizing plate was bonded to the other side (backlight side). The polarizing plates on both sides of the liquid crystal cell were arranged in crossed Nicols. The combination polarizing plate side of the liquid crystal panel was placed on a backlight (taken from the same LC-26GD1 as described above) to obtain a liquid crystal display device. About the liquid crystal display device, light leakage from a gap (butting portion) in a state where no voltage was applied (black display) was visually evaluated according to the following criteria.

(Combination type phase difference plate with adhesive layer)
A polarizing plate (NPF-SEG1224DU: NITTO DENKO (NITTO DENKO) Product), and the other side (backlight side) was bonded with a retardation layer with a combined pressure-sensitive adhesive layer, and a polarizing plate similar to the above was bonded. The polarizing plates on both sides of the liquid crystal cell were arranged in crossed Nicols. The absorption axis of the polarizing plate on the backlight side was arranged so as to be substantially parallel to the slow axis of the combined retardation plate. The side of the retardation plate with a combined pressure-sensitive adhesive layer of the liquid crystal panel is placed on a backlight (extracted from the same LC-26GD1 as described above to obtain a liquid crystal display device. No voltage is applied to the liquid crystal display device. The light leakage from the gap (butting portion) in (black display) was visually evaluated according to the following criteria.

(Luminance)
The luminance meter (CA-1500, manufactured by Minolta) was thus measured butt portion of the center brightness A (cd / cm ²⁾ and the peripheral area brightness B (cd / cm ^2). The difference (central luminance A−peripheral luminance B) was calculated from these values. In the combination type optical film polarizing plate, the central luminance A is measured for the abutting portion (streaks), and the peripheral luminance B is measured for the portions other than the abutting portion. On the other hand, in the laminated combination type optical film polarizing plate, since there are a plurality of abutting portions, the central luminance A is the brightest of the luminances measured among the abutting portions, and the peripheral luminance B is the abutting portion. The measurement was made at a place where (streak) was avoided. The same applies to the combination type optical film retardation plate and the laminated combination type optical film retardation plate.

(Visual criteria)
Visual observation was performed from a distance of 50 cm from the sample, and light leakage at the butting portion and streaks caused by the butting were evaluated in the following three stages.
(Double-circle): The butting | matching part cannot be visually recognized in the front and the diagonal direction.
○: The butt portion cannot be visually recognized in frontal observation, but can be visually recognized from an oblique direction.
X: The butt portion can be visually recognized by frontal observation.

In the example, the center luminance A of the butted portion is small, the difference (center luminance A−peripheral luminance B) is 20 cd / cm ² or less, and light leakage at the butted portion is suppressed. And the difference (center luminance A−peripheral luminance B) is greater than ²⁰ cd / cm ² , and the butt portion can be visually recognized. In addition, the combination type polarizing plates of Examples 1 to 4 and the retardation plate with the combination type adhesive layer of Example 9 satisfy the relationship t ≦ d × tan θ. On the other hand, in the combination type polarizing plate of Comparative Example 2 and the combination type phase difference plate with Comparative Adhesive Layer of Comparative Example 3, the inclination of the butt portion has a relationship of t> d × tan θ.

It is an example of the cross-sectional part of the combination type optical film (1) of this invention. It is an example of the cross-sectional part of the combination type optical film (1) of this invention. It is an example of the cross-sectional part of the combination type optical film (1) of this invention. It is an example of the cross-sectional part of the combination type optical film (1) of this invention. It is an example of the cross-sectional part of the combination type optical film (1) of this invention. It is an example of the cross-sectional part of the combination type optical film (1) of this invention. It is an example of the cross-sectional part of the combination type optical film (1) of this invention. It is an example of the cross-sectional part of the combination type optical film (1) of this invention. It is an example of the cross-sectional part of the combination type optical film (1) of this invention. It is an example of the cross-sectional part of the combination type optical film (2) of this invention. It is an example of the cross-sectional part of the combination type optical film (2) or (3) of this invention. It is an example of the cross-sectional part of the combination-type optical film (5) of this invention. It is an example of the cross-sectional part of what combined the optical film (1) and (5) of this invention. It is an example of the cross-sectional part of the combination type optical film (6) of this invention. It is an example of the cross-section part of what combined the combination type optical film (1) and (6) of this invention. It is an example of the cross-section part of what combined the combination type optical film (1) and (6) of this invention. It is a perspective view in case the easily peelable protective film is mounted on both surfaces of the combined optical film (1) of the present invention and an adhesive tape is attached. It is a perspective view in case the easily peelable protective film is mounted on both surfaces of the combined optical film (1) of the present invention and an adhesive tape is attached. It is an example of the cross-sectional part of the lamination | stacking combination type | mold optical film (11) of this invention. It is an example of the cross-sectional part of the lamination | stacking combination type | mold optical film (12) of this invention. In the lamination | stacking combination optical film (12) of this invention, it is an example of the cross-section part of what used the combination optical film (5). In the lamination | stacking combination optical film (12) of this invention, it is an example of the cross-section part of what used the combination optical film (6). In the lamination | stacking combination optical film (12) of this invention, it is an example of the cross-section part of what used the combination optical film (6). It is a perspective view in case the easily peelable protective film is mounted on both surfaces of the laminated combined optical film (12) of the present invention, and an adhesive tape is attached. It is an example of the cross-sectional part of the conventional combination type optical film.

Explanation of symbols

A Optical film A 'Optical film x Butt end face D Diffusion layer L1 Easy peel type protective film L2 Easy peel type protective film (separator)
P Adhesive layer T Adhesive tape F Film

Claims (41)

In a combined optical film formed by abutting at least one end face of a plurality of optical films with each other,
The butted end surfaces substantially match each other in shape, and the butted end surfaces have at least portions that are not perpendicular to the front and back surfaces of the optical film,
The butt end surface is butted so as not to have a continuous gap from the front surface to the back surface in the normal direction of the optical film.   The combined optical film according to claim 1, wherein the butt end surface is inclined in a plane from the front surface to the back surface of the optical film.   The combined optical film according to claim 2, wherein the angle of inclination (θ) between the end face and the normal to the optical film is 1 to 89 °. When the inclination angle of the butt end face is θ (°), the average gap between films in the butt portion is t (μm), and the thickness of the optical film is d (μm),
t ≦ d × tan θ,
1 ° ≦ θ ≦ 60 °,
The combined optical film according to claim 2, wherein the relationship is satisfied. In a combined optical film formed by abutting at least one end face of a plurality of optical films with each other,
The combined optical film is characterized in that the butted end surfaces are bonded with a bonding agent having substantially the same refractive index as that of the optical film. In a combined optical film formed by abutting at least one end face of a plurality of optical films with each other,
A butt end face is joined by dissolution and solidification with an organic solvent capable of dissolving the optical film, and a combined optical film. In a combined optical film formed by abutting at least one end face of a plurality of optical films with each other,
The combined optical film is characterized in that the butt end faces are bonded by heat sealing. In a combined optical film formed by abutting at least one end face of a plurality of optical films with each other,
A plurality of optical films have a diffusion layer and / or an optical film on the front surface and / or back surface, and a combined optical film. In a combined optical film formed by abutting at least one end face of a plurality of optical films with each other,
A combined optical film, wherein a diffusion layer and / or an optical film are provided on the front surface and / or the back surface of the combined optical film. The butted end surfaces of the optical film substantially match each other in shape, and the butted end surfaces have at least portions that are not perpendicular to the front and back surfaces of the optical film,
The combined optical film according to claim 8 or 9, wherein the butted end surfaces are butted so as not to have a continuous gap from the front surface to the back surface in the normal direction of the optical film.   The combined optical film according to claim 10, wherein the butt end surface is inclined in a plane from the front surface to the back surface of the optical film.   12. The combined optical film according to claim 11, wherein the angle of inclination ([theta]) between the end face and the normal to the optical film is 1 to 89 [deg.]. When the inclination angle of the butt end face is θ (°), the average gap between films in the butt portion is t (μm), and the thickness of the optical film is d (μm),
t ≦ d × tan θ,
1 ° ≦ θ ≦ 60 °,
The combination type optical film according to claim 11, wherein the relationship is satisfied.   14. The combined optical film according to claim 8, wherein the butted end surfaces of the optical film are bonded with a bonding agent having substantially the same refractive index as that of the optical film.   14. The combined optical film according to claim 8, wherein the butted end faces of the optical film are joined by dissolution and solidification with an organic solvent capable of dissolving the optical film.   14. The combined optical film according to claim 8, wherein the butted end faces of the optical film are bonded by heat fusion.   The combined optical film according to claim 1, wherein the optical film has a thickness of 500 μm or less.   The optical film is a polarizer, a protective film for a polarizer, or a polarizing plate in which a protective film is laminated on one side or both sides of a polarizer. 18. The combined optical film according to claim 1, . The combined optical film according to claim 18, wherein a polarizing plate using a polarizing plate as the optical film,
The combination type polarizing plate is measured for a liquid crystal panel in which the combination type polarizing plate is arranged on the backlight side of the liquid crystal cell, and the polarizing plate (not combined) is arranged in crossed Nicols on the viewing side of the liquid crystal cell. The difference between the central luminance A (cd / cm ² ) and the peripheral luminance B (cd / cm ² ) of the butt portion of the combination type polarizing plate (central luminance A−peripheral luminance B) is 20 cd / cm ² or less. The combination type optical film according to claim 18, wherein the combination type optical film is provided.   The combination type optical film according to claim 1, wherein the optical film is a retardation plate. A combination type retardation plate using a retardation plate as an optical film according to claim 20,
The combination type retardation plate is a liquid crystal panel in which polarizing plates (not combined) are arranged in crossed Nicols on both sides of the combination type retardation plate arranged on the backlight side adjacent to the liquid crystal cell, Center luminance A of the butted portion of the combined retardation plate measured for a liquid crystal panel arranged so that the absorption axis of the polarizing plate on the backlight side is substantially parallel to the slow axis of the combined retardation plate 21. The combination type according to claim 20, wherein a difference (central luminance A−peripheral luminance B) between (cd / cm ² ) and peripheral luminance B (cd / cm ² ) is ²⁰ cd / cm ² or less. Optical film.   The plurality of optical films are provided with an easily peelable protective film on the front surface and / or back surface, and an adhesive tape is placed on the adjacent protective film corresponding to the abutting portion in the combined optical film. The combined optical film according to any one of claims 1 to 8, or 10 to 21, wherein the protective film is attached and the protective films are connected to each other.   A laminated combined optical film, wherein at least two layers of the combined optical film according to claim 1 are laminated. A combined optical film formed by laminating a plurality of laminated optical films obtained by abutting at least one end face of a plurality of optical films with each other,
A laminated combined optical film, wherein at least one set of butted portions of the combined optical film of each layer is laminated so as not to overlap in a normal direction to the combined optical film. In the combination type optical film of at least one layer, the abutting end faces substantially coincide with each other, and the abutting end faces have at least portions that are not perpendicular to the front and back surfaces of the optical film;
The laminated combined optical film according to claim 24, wherein the butted end surfaces are butted so as not to have a continuous gap from the front surface to the back surface in the normal direction of the optical film.   26. The laminated combined optical film according to claim 25, wherein the butted end surface is inclined in a plane from the front surface to the back surface of the optical film.   27. The laminated combined optical film according to claim 26, wherein an angle (θ) between the end face and the normal to the optical film is 1 to 89 °. When the inclination angle of the butt end face is θ (°), the average gap between films in the butt portion is t (μm), and the thickness of the optical film is d (μm),
t ≦ d × tan θ,
1 ° ≦ θ ≦ 60 °,
28. The laminated combined optical film according to claim 27, wherein the following relationship is satisfied.   29. The laminated combination according to any one of claims 24 to 28, wherein at least one layer of the combination-type optical film has its butt end face bonded with a bonding agent having substantially the same refractive index as that of the optical film. Type optical film.   29. The laminated combination type according to any one of claims 24 to 28, wherein at least one layer of the combination type optical film has a butted end face joined by dissolution and solidification with an organic solvent capable of dissolving the optical film. Optical film.   The laminated combined optical film according to any one of claims 24 to 28, wherein the butted end surfaces of the combined optical film having at least one layer are bonded by heat fusion.   The plurality of optical films forming the combined optical film of the front surface and / or the back surface has a diffusion layer and / or an optical film on any one of the front surface, the back surface, and the inner surface. The laminated combination type optical film according to any one of claims 24 to 31.   32. A laminated combination type optical film comprising a diffusion layer and / or an optical film provided on any one of a front surface, a back surface and an inner surface of the laminated combination type optical film according to claim 24. the film.   34. The laminated combined optical film according to any one of claims 24 to 33, wherein the thickness of the optical film in each layer is 500 μm or less. The optical film in the one-layer combination optical film is a polarizer,
35. The laminated combined optical film according to claim 24, wherein the optical film in at least one other combined optical film is a protective film for a polarizer and forms a polarizing plate. .   35. The laminated combined optical film according to any one of claims 24 to 34, wherein the optical film used for the combined optical film of each layer is a polarizing plate. A laminated combined polarizing plate in which a polarizing plate is formed by combining each layer according to claim 35, or a laminated combined polarizing plate using a polarizing plate as a combined optical film of each layer according to claim 36,
The laminated combined polarizing plate is a liquid crystal panel in which the laminated combined polarizing plate is disposed on the backlight side of the liquid crystal cell, and on the viewing side of the liquid crystal cell, a polarizing plate (not combined) is disposed in crossed Nicols. The difference between the central luminance A (cd / cm ² ) and the peripheral luminance B (cd / cm ² ) of the butt portion of the laminated combination type polarizing plate (center luminance A−peripheral luminance B) measured with respect to 20 cd / cm 37. The laminated combined optical film according to claim 35 or 36, which is ² or less.   35. The laminated combined optical film according to any one of claims 24 to 34, wherein the optical film used for the combined optical film of each layer is a retardation plate. A laminated combination type retardation plate using a retardation plate as a combination type optical film of each layer according to claim 38,
The multilayer combination type retardation plate is a liquid crystal panel in which polarizing plates (not combined) are arranged in crossed Nicols on both sides of the multilayer combination type retardation plate arranged on the backlight side adjacent to the liquid crystal cell. The butt portion of the laminated combination type retardation plate measured for the liquid crystal panel arranged so that the absorption axis of the polarizing plate on the backlight side is substantially parallel to the slow axis of the laminated combination type retardation plate The difference between the central luminance A (cd / cm ² ) and the peripheral luminance B (cd / cm ² ) is (center luminance A−peripheral luminance B) of 20 cd / cm ² or less. The laminated combined optical film described.   The plurality of optical films forming the combined optical film on the front surface and / or the back surface are equipped with an easily peelable protective film, and the adjacent protections corresponding to the butted end surfaces of the combined optical film The laminated combination type optical film according to any one of claims 24 to 32 or 34 to 39, wherein an adhesive tape is stuck on the film, and the protective films are connected to each other.   An image display device comprising the combined optical film according to any one of claims 1 to 22 or the laminated combined optical film according to any one of claims 23 to 40.

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