JP2021054061A - Laminate film - Google Patents

Abstract

To provide a laminate film for displaying a projection image, in which visibility of information from outside such as landscapes, display performance of information from the projection member and reproducibility of the color are excellent and the distortion is suppressed.SOLUTION: A laminate film for image displaying is a laminate film having a plurality of different thermoplastic resins laminated more than 50 layers, in which the transmittance of light incident perpendicularly to the laminate film surface is 50% or higher, and when the reflectance (%) of each P wave when incident at an angle of 20°, 40°, 70°is set to Rp20, Rp40, and Rp70, the relationship of Rp20≤Rp40<Rp70 is satisfied, and Rp70 is 30% or larger, and the saturation of the reflected light of the P wave when it is incident at an angle of 70°with respect to the normal of the laminated film surface is 20 or smaller, and the thermal shrinkage when heated at 150°C for 30 minutes in any direction of an alignment axis direction or a direction orthogonal to an alignment axis direction of the laminated film is 1% or larger and 5% or smaller.SELECTED DRAWING: None

Description

The present invention relates to a laminated film and a projected image display member used for a projected image display member, a display device using the projected image display member, a head-up display, and a head-mounted display.

A head-up display (HUD) is known as a means for displaying information directly in the human field of view. For example, while driving a car, information such as the speed of instruments is directly projected on the windshield as a virtual image, so that the driver can drive without changing the field of view, which leads to accident prevention. Normally, light emitted from a projector such as a small liquid crystal projector is transmitted and reflected by a display unit made of a transparent base material containing a half mirror material. The observer acquires the information displayed on the display unit and simultaneously acquires the external information such as the outside scenery through the display unit.

As a display device using the same technique, there is a head-mounted display used for AR (Augmented Reality). A head-mounted display (HMD) used for AR applications has a glass-type display device attached to the head to visually recognize information from the outside through the glass and to display information from a projector provided on the side. It is transmitted and displayed on the glass.

In the display device used for HUD and HMD, from the viewpoint of safety and visibility, for example, in Patent Documents 1 and 2, a head-up display using a film having polarization reflection characteristics that reflects only the polarized light emitted from the liquid crystal projector. It is shown. However, since light from the outside such as a landscape is often unpolarized, there is a problem that visibility in the front direction is impaired when a film having polarization reflection characteristics is used.

As a method for solving the above problems, for example, Patent Document 3 discloses an HUD and an HMD using a film that has both transparency in the front direction and displayability of information projected from an oblique direction.

Special Table 2006-512622 JP-A-2017-206012 International Publication 1997/36195

When the multilayer laminate disclosed in Patent Document 3 is used for the HUD or HMD, the transparency in the front direction is certainly excellent and the visibility of information from the outside such as a landscape is improved, but on the other hand, from the projection member. There was a problem that the information was colored and the color was changed. Further, in the film described in Patent Document 3, when the above film is laminated or encapsulated on a transparent base material for displaying information, distortion generated in the film cannot be suppressed and a good appearance can be obtained. There was no challenge. Therefore, the present invention is intended to solve the above-mentioned problems, and is excellent in visibility of information from the outside such as a landscape, displayability of information from a projection member and reproducibility of color, and projection with suppressed distortion. An object of the present invention is to provide a laminated film for an image display member, a projected image display member, and a display device using the projected image display member.

The present invention is intended to solve the above-mentioned problems, and is a laminated film in which 50 or more layers of different thermoplastic resins are laminated, and has a transmittance of light vertically incident on the laminated film surface. Is 50% or more, and the reflectance (%) of each P wave when it is incident at angles of 20 °, 40 °, and 70 ° with respect to the normal of the laminated film surface is set to Rp20, Rp40, and Rp70. In this case, the relationship of Rp20≤Rp40 <Rp70 is satisfied, Rp70 is 30% or more, and the saturation of the reflected light of the P wave when it is incident at an angle of 70 ° with respect to the normal of the laminated film surface is 20 or less, and the heat shrinkage rate when the laminated film is heated at 150 ° C. for 30 minutes in either the main orientation axis direction or the direction orthogonal to the main orientation axis direction is 1% or more and 5% or less. It is a laminated film for a display member.

According to the present invention, even when used as a display unit of a head-up display (HUD) or a head-mounted display (HMD), the visibility of information from the outside such as a landscape, and the displayability and color of information from a projection member It is possible to obtain a display device having excellent reproducibility and suppressing distortion.

The schematic diagram explaining the azimuth angle of the laminated film of this invention. The schematic diagram explaining the layer thickness of the layer A and the layer B of the laminated film of this invention. The schematic diagram which shows the reflection characteristic in an oblique direction of a transparent member and the laminated film of this invention. The schematic diagram which shows the reflection characteristic in the oblique direction of the projection image display member of this invention.

Hereinafter, embodiments of the present invention will be described, but the present invention is not construed as being limited to embodiments including the following examples, and the object of the invention can be achieved and the gist of the invention is deviated. Of course, various changes are possible within the scope of not being. Further, for the purpose of simplifying the description, a part of the description will be given by taking as an example a laminated film having a structure in which two different types of thermoplastic resin layers are alternately laminated, which is one of the preferred embodiments of the present invention. However, it should be understood in the same manner even when three or more kinds of thermoplastic resins are used. Hereinafter, the laminated film for the projected image display member may be simply referred to as a “laminated film”.

The laminated film of the present invention needs to be formed by laminating 50 or more layers of different thermoplastic resins. Preferably, a plurality of different thermoplastic resins are alternately laminated in 50 or more layers. The difference in the thermoplastic resin here means that the refractive index of the thermoplastic resin differs by 0.01 or more in either the two orthogonal directions arbitrarily selected in the plane of the film and the direction perpendicular to the plane. Point to.

The term "alternately laminated" as used herein means that layers made of different thermoplastic resins are laminated in a regular arrangement in the thickness direction. When there are a thermoplastic resin A and a thermoplastic resin B, if the layers made of the respective thermoplastic resins are expressed as layers A and B, they are laminated in order such as A (BA) n (n is a natural number). Is. When there are a thermoplastic resin A, a thermoplastic resin B, and a thermoplastic resin C, if the layer made of each thermoplastic resin is expressed as a layer A, a layer B, and a C layer, all the layers are included. The sequence is not particularly limited, but one example thereof is one in which C (BA) nC, C (ABC) n, C (ACBC) n, etc. are stacked in order with a certain regularity. The "layer made of the thermoplastic resin A" means a layer containing 70% by mass or more and 100% by mass or less of the thermoplastic resin A in all the components constituting the layer, and hereinafter, "a layer made of the thermoplastic resin B". , "Layer made of thermoplastic resin C" and the like can be interpreted in the same way.

By alternately laminating resins having different optical properties such as refractive index in this way, it is possible to develop interference reflection that reflects light of a wavelength designed from the relationship between the difference in refractive index of each layer and the layer thickness. It will be possible.

Further, when the number of layers to be laminated is 49 or less, high reflectance cannot be obtained in a desired band. Further, as the number of layers increases, the above-mentioned interference reflection can achieve a high reflectance for light in a wider wavelength band, and a laminated film that reflects light in a desired band can be obtained. From the above viewpoint, the number of layers is preferably 400 layers or more, and more preferably 800 layers or more. In addition, although there is no upper limit to the number of layers, as the number of layers increases, the manufacturing cost increases due to the increase in size of the manufacturing apparatus, and the handleability deteriorates due to the thickening of the film. Therefore, in reality, 10,000 The practical range is about one layer.

The laminated film of the present invention needs to have a transmittance of 50% or more of light incident on the film surface perpendicularly (meaning an angle of 0 ° with respect to the normal of the film surface). Here, the fact that the transmittance of vertically incident light is 50% or more means that the average transmittance of the film at a wavelength of 450 to 650 nm is 50% or more. Due to the high transmittance of light in the visible light region with a wavelength of 450 to 650 nm, excellent transparency is provided to information from the outside such as landscapes even when incorporated as a display base material for HUDs and HMDs. Can be shown. From the above viewpoint, the transmittance is preferably 70% or more, more preferably 80% or more, and further preferably 90% or more. When the transmittance is 90% or more, the transparency is the same as that of a transparent member such as ordinary glass, glasses, and an acrylic plate, so that the material can be used without imposing any burden on the user.

In order to obtain such a laminated film, it is achieved by reducing the difference in refractive index between the two thermoplastic resins in the direction parallel to the film surface as a final product. If the difference in refractive index in the direction parallel to the film surface is 0.06 or less, the transmittance is 50% or more, if it is 0.04 or less, the transmittance is 70% or more, and if the difference in refractive index is 0.02 or less. For example, if the transmittance is 80% or more and the refractive index difference is 0.01 or less, the transmittance can be easily set to 90% or more. The "difference in refractive index in the direction parallel to the film surface" is the difference in the refractive index between the two types of layers (when the two types of layers are layer A and layer B, the difference between layers A and B). (Difference in in-plane refractive index).

The laminated film of the present invention has reflectance characteristics of Rp20, Rp40, and the reflectance (%) of each P wave when it is incident at angles of 20 °, 40 °, and 70 ° with respect to the normal of the film surface. When Rp70 is set, it is necessary to satisfy the relationship of Rp20 ≦ Rp40 <Rp70. The reflectance referred to here is an average reflectance having a wavelength of 450 to 650 nm. In the case of a general transparent substrate such as glass or transparent film, the reflectance of P wave, which is one of the polarized light, decreases as the incident angle is gradually increased from 20 ° with respect to the normal line of the film surface. At an angle called Brewster's angle, the reflectance becomes zero. Therefore, when information is projected onto the transparent substrate from an incident angle near the Brewster's angle, the displayability is poor due to the low reflectance. Therefore, when the reflectances of the P waves when they are incident at angles of 20 °, 40 °, and 70 ° with respect to the normal of the film surface are Rp20, Rp40, and Rp70, the relationship of Rp20≤Rp40 <Rp70 is established. When satisfied, since the angle corresponding to the Brewster's angle is not provided, the information can be clearly displayed even when the information is projected from an oblique direction with respect to the film surface.

Further, the laminated film of the present invention also needs to have Rp70 of 30% or more. If the reflectance of the P wave at 70 ° incident is 30% or more, it is possible to obtain a highly clear display particularly in the case of a method of projecting information from the side surface such as the HUD. Preferably, the reflectance at 70 ° incident is 50% or more, and as the reflectance increases, it becomes easier to obtain a display device having excellent displayability. In order to obtain such a laminated film, it is achieved by increasing the difference in refractive index between the two thermoplastic resins in the direction perpendicular to the film surface as a final product, and the difference in refractive index in the direction perpendicular to the film surface is increased. If is 0.08 or more, the reflectance can be easily set to 30% or more, and if the refractive index difference is 0.12 or more, the reflectance can be easily set to 50% or more.

The laminated film of the present invention preferably has an azimuth angle variation of Rp70 of 10% or less. Here, the azimuth variation is measured at each azimuth angle (0 °, 45 °, 90 °, 135 °) with the azimuth angle in the main orientation axis direction of the laminated film of the present invention set to 0 ° as shown in FIG. It represents the difference between the maximum value and the minimum value of Rp70. When the azimuth angle variation of Rp70 is 10% or less, the displayability such as the brightness of the information can be maintained at the same level regardless of the direction in which the information (image or the like) is projected. In order to reduce the azimuth angle variation of Rp70, for example, it is possible to reduce the in-plane refractive index unevenness of the laminated film of the present invention, and in order to reduce the in-plane refractive index unevenness of the film, it is possible to reduce the in-plane refractive index unevenness of the film. At the time of biaxial stretching, the film may be stretched so as to reduce the difference in orientation between the longitudinal direction and the width direction of the film.

The method of adjusting the reflection wavelength of the laminated film in the wavelength range of 450 to 650 nm includes the difference in the plane-direct refractive index between the layers A and B, the number of layers, the layer thickness distribution, and the film forming conditions (for example, stretching ratio, stretching speed, stretching temperature). , Heat treatment temperature, heat treatment time) and the like. As for the constitution of the layer A and the layer B, it is preferable that the layer A is made of a crystalline thermoplastic resin and the layer B is made of a resin containing an amorphous thermoplastic resin as a main component. Here, the resin containing an amorphous thermoplastic resin as a main component means that the weight fraction of the amorphous thermoplastic resin is 70% or more. Since the reflectance is high and the number of layers can be reduced, it is preferable that the difference in the plane-direct refractive index between the layer A and the layer B is high. As for the layer thickness distribution, it is preferable that the optical thicknesses of the adjacent layers A and B satisfy the following formula (A).

Here λ is the reflected wavelength, n _A is the surface of layer A straight refractive index, the thickness of d _A is the layer A, n _B is the orthogonal refractive index of the layer B, d _B is the thickness of the layer B.

The layer thickness distribution is constant from one of the film surfaces to the opposite surface, the layer thickness distribution increases or decreases from one of the film surfaces to the opposite surface, or from one of the film surfaces. A layer thickness distribution that increases and then decreases toward the center of the film, a layer thickness distribution that increases after the layer thickness decreases toward the center of the film from one side of the film surface, and a combination of these distributions are preferable. As for the way of changing the layer thickness distribution, those that change continuously such as linear, geometric progression, and difference sequence, and layers of about 10 to 50 layers have almost the same layer thickness, and the layer thickness is stepped. Those that change are preferable.

A layer having a layer thickness of 3 μm or more can be preferably provided as a protective layer on both surface layers of the laminated film. The thickness of the protective layer is preferably 5 μm or more, more preferably 10 μm or more. By increasing the thickness of the protective layer, flow marks during film formation can be suppressed, deformation of the thin film layer in the multilayer laminated film can be suppressed during the laminating process with other films and molded bodies, and after the laminating process, and pressure resistance can be suppressed. Can be mentioned. The thickness of the multilayer laminated film of the present invention is not particularly limited, but is preferably, for example, 20 μm to 300 μm. If it is less than 20 μm, the film may be weak and the handleability may be deteriorated. On the other hand, if the thickness is 300 μm or more, the film may be too stiff and the moldability may be deteriorated.

Primer layer, hard coat layer, abrasion resistant layer, scratch prevention layer, antireflection layer, color correction layer, ultraviolet absorption layer, light stabilization layer (HALS), heat ray absorption layer, printing on at least one surface of the laminated film. It may have a functional layer such as a layer, a gas barrier layer, and an adhesive layer. These layers may be one layer or multiple layers, and one layer may have a plurality of functions. Further, the multilayer laminated film may contain additives such as an ultraviolet absorber, a light stabilizer (HALS), a heat ray absorber, a crystal nucleating agent, and a plasticizer. It should be noted that these components can be used in combination as long as the effects of the present invention are not impaired.

In the laminated film of the present invention, the saturation of the reflected light of the P wave when it is incident at an angle of 70 ° with respect to the normal of the film surface needs to be 20 or less. The saturation referred to here is the XYZ value under the C light source and the XYZ using the reflection spectrum of the P wave measured at a certain incident angle in the spectrophotometer, the spectral distribution of the C light source, and the color matching function of the XYZ system. Let it be the saturation C ^* value calculated using the value. By setting the saturation to 20 or less, there is little coloring and when used as a transparent base material for HUDs and HMDs, the color recognition of information from the outside such as landscapes is excellent, and the color recognition of the display from the projection member is also improved. It is possible to obtain an excellent display member. From the above viewpoint, the saturation is more preferably 10 or less, still more preferably 5 or less. As the saturation decreases, the degree of coloration of the laminated film decreases, and if the saturation is 5 or less, it can be used without discomfort in color recognition before and after mounting when used as a transparent base material for HUD or HMD, and it is displayed. The information you want can be expressed in accurate colors.

In order to obtain such a laminated film, the deviation of the transmittance of the P wave having a wavelength of 450 to 650 nm when it is incident at an angle of 70 ° with respect to the normal direction of the laminated film surface may be 10% or less. preferable. The transmittance deviation referred to here is the deviation of the transmittance data of 201 points collected at a wavelength interval of 1 nm in the wavelength section of 450 to 650 nm. Since the deviation of the transmittance at a wavelength of 450 to 650 nm is 10% or less in this way, the light corresponding to RGB can be uniformly transmitted, so that the coloring of the transmitted light is suppressed and the saturation of 20 or less can be easily achieved. It can be achieved. More preferably, the deviation of the transmittance of the P wave incident at an angle of 70 ° at a wavelength of 450 to 650 nm is 5% or less, and in this case, the saturation can be achieved to 5 or less. When used, it can be considered to have excellent visibility of information from the outside such as a landscape and display from a projection member.

FIG. 2 will be described as an example of a method in which the deviation of the transmittance of the P wave having a wavelength of 450 to 650 nm when it is incident at an angle of 70 ° with respect to the normal direction of the laminated film surface is 10% or less. As shown in FIG. 2, according to the formula (1), the thickness of the layer A and the thickness of the layer B that reflect the wavelength range of 450 nm to 650 nm are uniformly arranged. Here, FIG. 2 is a multilayer laminated film having 401 layers, in which the plane-direct refractive index (n _A ) of layer A is 1.5 and the plane-direct refractive index (n _B ) of layer B is 1.6, and the film surface. This is an example of the ideal layer thickness distribution of the layers A and B up to the position 401 of the layer on the opposite film surface, where the position of the layer is 1. Actually, the design accuracy of the device and the operational stability of the film forming device affect the error from the ideal layer thickness as shown in FIG. 2, but each of the layers from the layer position 1 to the layer position 401. If the error in the position of the layers averaged from layers 1 to 401 is within ± 10%, the wavelength of the P wave when incident at an angle of 70 ° with respect to the normal direction of the laminated film surface is 450 to The deviation of the transmittance at 650 nm can be 10% or less.

Similarly, it is also preferable that the difference between the maximum value and the minimum value of the reflectance of the P wave having a wavelength of 450 to 650 nm when incident at an angle of 70 ° with respect to the normal direction of the laminated film surface is less than 40%. More preferably, the difference between the maximum value and the minimum value is less than 20%, more preferably less than 10%. If the deviation of the transmittance of the P wave with a wavelength of 450 to 650 nm is small, it is easy to obtain a low-saturation one, but by further reducing the difference between the maximum value and the minimum value, coloring due to local reflection can be suppressed. , It becomes easy to suppress the saturation. An example of a method in which the difference between the maximum value and the minimum value of the reflectance of the P wave having a wavelength of 450 to 650 nm when it is incident at an angle of 70 ° with respect to the normal direction of the laminated film surface is less than 40%. , The thickness of A and the thickness of layer B are uniformly arranged as shown in FIG. Here, as the allowable value of the actual error with respect to the ideal layer thickness distribution in FIG. 2, the error obtained by averaging the error at each layer position from the layer position 1 to the layer position 401 from the layer 1 to 401. The number of layers having an error of ± 10% or more and a layer thickness error of ± 10% or more is continuously set to 10 layers or less.

When a film is attached to a transparent base material or encapsulated, an adhesive layer is generally provided between the transparent base material and the film, and heating and pressurization are performed in order to improve adhesion. During this processing, the film is distorted due to uneven thickness of the adhesive layer, difference in expansion coefficient and shrinkage between the adhesive layer and the film, uneven heating / pressurization, etc., and the distortion causes light to be scattered and diffused reflection. Therefore, when the distorted processed product is used as the projected image display member, the projected image is distorted. Since a laminated film has an interface formed of different types of resin in it, light scattering and reflection due to the interface are added in addition to light scattering and diffuse reflection by the film surface, so that the laminated film has more unevenness than a film made of one type of resin. It becomes more noticeable. Therefore, if a multilayer laminated film in which unevenness is unlikely to occur can be used, a projected image display member without image distortion can be produced.

The strain generated by the processing can be alleviated by heating the film at a temperature higher than the glass transition temperature (Tg) of the adhesive layer and heat-shrinking the film. Therefore, from the viewpoint of processing quality when the laminated film of the present invention is laminated or encapsulated on a transparent base material, the laminated film of the present invention is oriented in the main orientation axis direction or the main orientation axis direction of the laminated film. It is necessary that the heat shrinkage rate when heated at 150 ° C. for 30 minutes in the orthogonal direction is 1% or more and 5% or less. By setting the heat shrinkage rate when heated at 150 ° C. for 30 minutes to 1% or more, a distortion mitigation effect is generated. On the other hand, if the heat shrinkage rate when heated at 150 ° C. for 30 minutes is higher than 5%, the shrinkage of the film becomes too large, and there may be a problem that voids or sink marks occur at the edges of the transparent base material. In order to obtain a highly strain-relieving effect, the heat shrinkage rate when heated at 150 ° C. for 30 minutes is preferably 2% or more and 5% or less.

In the laminated film of the present invention, the phase difference is preferably 2000 nm or less. In order to increase the transmittance of light incident perpendicular to the film surface, it is necessary to reduce the difference in refractive index between the two thermoplastic resins in the direction parallel to the film surface as a final product. When there is anisotropy in the orientation state between the width direction of the film and the flow direction orthogonal to the width direction, if the resin is selected so that the difference in the refractive index in either direction becomes small, the resin is orthogonal. The refractive index in the direction becomes large. As a result, it can be difficult to achieve transparency in the direction perpendicular to the film surface. Therefore, by setting the phase difference, which is a parameter related to the anisotropy of the orientation state, to 2000 nm or less, the anisotropy of the orientation state in the film surface can be reduced, and the transmittance of light vertically incident on the film surface can be reduced. Is easily set to 50% or more, preferably 70% or more. From the above viewpoint, the phase difference is preferably 1000 nm or less, and more preferably 500 nm or less. The smaller the phase difference, the easier it is to reduce the difference in refractive index between the two thermoplastic resins in the direction parallel to the film surface in any of the flow directions orthogonal to the width direction of the film, and the film is vertically incident on the film surface. It is possible to increase the light transmission rate. That is, the lower limit is not particularly limited, but is 10 nm from the viewpoint of feasibility. It is also possible to suppress rainbow unevenness when the projected image display member using the laminated film of the present invention is visually recognized. In addition, since the small phase difference also suppresses the azimuth unevenness of the reflectance of the P wave, the sharpness of the displayed information is constant regardless of the azimuth angle at which the information is projected onto the projected image display member. Become. This effect is one of the features of the laminated film of the present invention, and is an effect that cannot be achieved by the polarizing reflection film described in Patent Documents 1 and 2.

In order to obtain such a laminated film, it is preferable that the laminated film has one melting point and the melting enthalpy is 20 J / g or more. The melting point and the enthalpy of fusion here are those measured by a measuring method described later using differential calorimetry (DSC). In order to reduce the difference in refractive index in the direction parallel to the film surface and increase the difference in refractive index in the direction perpendicular to the film surface, one of the thermoplastic resins is strongly oriented in the direction parallel to the film surface. (The refractive index in the direction parallel to the film surface is large and the refractive index in the direction perpendicular to the film surface is small), while the other thermoplastic resin maintains isotropic properties (film surface). It is important that the refractive index in the direction parallel to and perpendicular to is the same).

Having one melting point means that among a plurality of different thermoplastic resins, only one is oriented / crystallized thermoplastic resin, and the other thermoplastic resins are amorphous without orientation. It shows that it is in a state, and when the resin is selected so as to reduce the difference in refractive index in the direction parallel to the film surface, it becomes easy to take a large difference in refractive index in the direction perpendicular to the film surface. .. Further, the fact that the melting enthalpy is 20 J / g or more indicates that the orientation and crystallization of the resin having a melting point is progressing, and it is easy to increase the difference in refractive index in the direction perpendicular to the film surface. Become.

More preferably, the in-plane average refractive index of the outermost layer constituting the laminated film is 1.61 or more. By increasing the average refractive index in the in-plane direction of the film, the difference in refractive index in the direction perpendicular to the film surface can be easily increased. More preferably, the in-plane average refractive index is 1.63 or more.

The thermoplastic resin used in the present invention includes chain polyolefins such as polyethylene, polypropylene, poly (4-methylpentene-1) and polyacetal, ring-opening metathesis polymerization of norbornenes, addition polymerization, and addition copolymerization with other olefins. Combined alicyclic polyolefins, polylactic acid, biodegradable polymers such as polybutylsuccinate, polyamides such as nylon 6, nylon 11, nylon 12, nylon 66, aramid, polymethylmethacrylate, polyvinyl chloride, polyvinylidene chloride , Polyvinyl alcohol, polyvinyl butyral, ethylene vinyl acetate copolymer, polyacetal, polyglucolic acid, polystyrene, styrene copolymer polymethylmethacrylate, polycarbonate, polypropylene terephthalate, polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate and other polyesters. , Polyether sulfone, polyether ether ketone, modified polyphenylene ether, polyphenylene sulfide, polyetherimide, polyimide, polyarylate, tetrafluorinated ethylene resin, trifluoroethylene resin, trifluorochloride ethylene resin, tetrafluoride ethylene -6 Propropylene fluorinated copolymer, polyvinylidene fluoride and the like can be used. Among these, polyester is particularly preferable from the viewpoint of strength, heat resistance, transparency and versatility. These may be copolymers or mixtures of two or more resins.

As the polyester, a polyester obtained by polymerization of an aromatic dicarboxylic acid or a monomer containing an aliphatic dicarboxylic acid and a diol as main constituents is preferable. Here, as the aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyl Examples thereof include a dicarboxylic acid, a 4,4'-diphenyl ether dicarboxylic acid, and a 4,4'-diphenylsulfone dicarboxylic acid. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dimer acid, dodecandioic acid, cyclohexanedicarboxylic acid and their ester derivatives. Of these, terephthalic acid and 2,6 naphthalenedicarboxylic acid, which exhibit a high refractive index, are preferable. Only one of these acid components may be used, two or more of these acid components may be used in combination, and an oxyacid such as hydroxybenzoic acid may be partially copolymerized.

Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. , 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis (4-) Hydroxyethoxyphenyl) propane, isosorbate, spiroglycol and the like can be mentioned. Of these, ethylene glycol is preferably used. Only one of these diol components may be used, or two or more of these diol components may be used in combination.

The thermoplastic resin of the present invention is, for example, among the above polyesters, polyethylene terephthalate and its polymer, polyethylene naphthalate and its copolymer, polybutylene terephthalate and its copolymer, polybutylene naphthalate and its copolymer, and the like. Further, it is preferable to use polyhexamethylene terephthalate and its copolymer, polyhexamethylene naphthalate and its copolymer, and the like.

As a preferable combination of the thermoplastic resins used in the laminated film of the present invention, it is first preferable that the absolute value of the difference in SP values of each thermoplastic resin is 1.0 or less. When the absolute value of the difference between the SP values is 1.0 or less, delamination is less likely to occur. More preferably, polymers having different optical properties are made up of combinations with the same basic skeleton. The basic skeleton referred to here is a repeating unit that constitutes a resin. For example, when polyethylene terephthalate is used as one of the thermoplastic resins, it is the same as polyethylene terephthalate from the viewpoint that a highly accurate laminated structure can be easily realized. It is preferable to contain ethylene terephthalate, which is the basic skeleton of. When thermoplastic resins having different optical properties are resins containing the same basic skeleton, the lamination accuracy is high and delamination at the lamination interface is less likely to occur.

In particular, in the laminated film of the present invention, among the alternately laminated layers, the resin constituting one layer (layer A) contains crystalline polyester, and the resin constituting the other layer (layer B) is amorphous. It is preferably a sex polyester. The amorphous resin referred to here is a resin heated at a temperature rise rate of 20 ° C./min from 25 ° C. to 300 ° C. at a temperature rise rate of 20 ° C./min according to JIS K7122 (1987) (1st RUN). After holding for 5 minutes in that state, the mixture was rapidly cooled to a temperature of 25 ° C. or lower, and then heated again from room temperature to a temperature of 300 ° C. at a heating rate of 20 ° C./min. In the differential scanning calorimetry chart, the resin having a crystal melting heat amount ΔHm obtained from the peak area of the melting peak is 5 J / g or less, and more preferably a resin showing no peak corresponding to crystal melting. When a crystalline thermoplastic resin is used on one side of the thermoplastic resin and an amorphous thermoplastic resin is used on the other side, even when a laminated film is used, only one melting point is shown.

The laminated film of the present invention preferably contains a polycyclic aromatic compound as an amorphous thermoplastic resin as a copolymerization component. By including a polycyclic aromatic compound such as naphthalene or anthracene, it becomes easy to increase the refractive index. More preferably, it is a copolymer containing three or more kinds of dicarboxylic acids and diols. In the case of a thermoplastic resin consisting of one type of dicarboxylic acid and one type of diol, orientation and crystallization may be promoted during stretching due to its high symmetry, and it may not be possible to maintain an amorphous state, but there are three or more types. By containing a copolymer containing a dicarboxylic acid and a diol, it becomes possible to maintain an amorphous state without progressing orientation and crystallization when stretched.

Further, in the laminated film of the present invention, it is preferable that any layer constituting the laminated film contains a structure derived from an alkylene glycol having a number average molecular weight of 200 or more. As described above, it is necessary to contain a large amount of aromatics in order to increase the refractive index, but it is easy to efficiently reduce the glass transition temperature while maintaining the refractive index by further containing a structure derived from alkylene glycol. As a result, a laminated film having an in-plane average refractive index of 1.61 or more and a glass transition temperature of 90 ° C. or less of each layer constituting the laminated film can be easily obtained. Particularly preferably, the thermoplastic resin constituting the layer B is amorphous and contains a structure derived from an alkylene glycol having a number average molecular weight of 200 or more, and more preferably from an amorphous thermoplastic resin. The layer is composed only of an amorphous thermoplastic resin containing a structure derived from alkylene glycol. By using a thermoplastic resin containing a structure derived from alkylene glycol mixed with another amorphous resin in a small amount, the glass transition temperature is further lowered efficiently while maintaining the refractive index of the amorphous resin. It becomes possible. Furthermore, by making the thermoplastic resin itself a copolymer containing a structure derived from alkylene glycol, a thermoplastic resin containing a structure derived from alkylene glycol can be formed on the film surface even when processed under high temperature conditions. This is preferable because it can suppress precipitation.

Examples of the alkylene glycol include polyethylene glycol, polytrimethylene glycol, polytetramethylene glycol and the like. The molecular weight of the alkylene glycol is preferably 200 or more and 2000 or less. When the molecular weight of the alkylene glycol is less than 200, the alkylene glycol is not sufficiently incorporated into the polymer due to its high volatility when synthesizing the thermoplastic resin, and as a result, the effect of lowering the glass transition temperature is sufficient. May not be obtained. Further, when the molecular weight of the alkylene glycol is larger than 2000, the reactivity may be lowered when the thermoplastic resin is produced, which may make the film unsuitable for production.

More preferably, in the laminated film of the present invention, the thermoplastic resin constituting the layer B contains a structure derived from two or more kinds of aromatic dicarboxylic acids and two or more kinds of alkyldiols, and has at least a number average molecular weight of 200. It contains the structure derived from the above alkylene glycol. The thermoplastic resin B used in the laminated film of the present invention realizes a high refractive index comparable to that of the oriented crystalline thermoplastic resin in an amorphous manner, and has a glass transition temperature that can be co-stretched with the crystalline thermoplastic resin. Need to show. It is difficult to meet all of these requirements with a single dicarboxylic acid or alkylene diol. Therefore, by containing two or more types of aromatic dicarboxylic acids and two or more types of alkyldiols, a total of four types can be used to increase the refractive index with the aromatic dicarboxylic acid and lower the glass transition temperature with a plurality of alkyldiols. Decrystallization can be achieved by containing the above dicarboxylic acid and diol.

In addition, various additives such as antioxidants, heat-resistant stabilizers, weather-resistant stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, and charges are contained in the thermoplastic resin. Inhibitors, nucleating agents and the like can be added alone or in combination to the extent that their properties are not deteriorated.

In the laminated film of the present invention, it is preferable that the value Tg1 of 1stRun and the value Tg2 of 2ndRun satisfy the relationship of Tg1-Tg2> 0 with respect to the glass transition temperature (Tg unit: ° C.) determined by the differential scanning calorimeter (DSC). .. Here, the measurement conditions of the glass transition temperature are as follows. The DSC curve of the measurement sample is measured according to JIS-K-7122 (1987) using differential calorimetry (DSC). In the test, the temperature is raised from 25 ° C. to 300 ° C. at 20 ° C./min, the DSC curve of the measurement sample is measured (1stRun), then rapidly cooled with liquid nitrogen, and again from 25 ° C. to 300 ° C. 20 ° C. The temperature is raised at ° C./min and the DSC curve of the measurement sample is measured (2nd Run). Let the glass transition temperature in the DSC curve of the 1st Run be Tg1 and the glass transition temperature in the DSC curve of the 2nd Run be Tg2. When there are a plurality of glass transition temperatures in the DSC curve, the highest glass transition temperature is Tg1 or Tg2.

In order to suppress strain, which is a subject of the present invention, it is preferable to increase the heat shrinkage rate at 150 ° C. for 30 minutes, and one of the methods is to use a crystalline polyester having a low Tg for the layer A. When Tg is low, the start temperature of heat shrinkage is lowered and the heat shrinkage rate is high, so that the effect of suppressing distortion is high. On the other hand, it is not preferable that the Tg of the amorphous polyester of layer B is low. Since the amorphous resin is rapidly softened when heated at a temperature exceeding Tg, unevenness is generated in the layer B during processing, and the unevenness causes distortion of the laminated film. Therefore, the amorphous polyester of layer B preferably has a high Tg, and preferably has a higher Tg than the crystalline polyester of layer A. Since the layer A is crystallized, unevenness is unlikely to occur in the layer A even if it is processed with heat having a temperature exceeding Tg. Therefore, when the Tg of the layer A is lower than the Tg of the layer B, the start temperature of the heat shrinkage of the laminated film is lowered and the heat shrinkage rate is high, and the Tg of the layer B is higher than the Tg of the layer A during processing. It is possible to suppress the occurrence of unevenness of the laminated film, and it is possible to further suppress the distortion of the laminated film generated during processing.

Regarding the glass transition temperature (Tg) of the laminated film obtained by the differential scanning calorimeter (DSC), the relationship between the 1stRun value Tg1 and the 2ndRun value Tg2 being Tg1-Tg2> 0 indicates that the Tg of layer A is a layer. It means that it is lower than Tg of B. At the time of 1st Run measurement, Tg does not appear because the layer A in the laminated film which is the measurement sample is crystallized, and Tg1 appears as Tg of the layer B. At the end of the 1st Run measurement, the laminated film is in a molten state, both layer A and layer B are melted, and at least a part of each other is mixed. After that, when the measurement sample is rapidly cooled and the 2nd Run measurement is started in an amorphous state, Tg (Tg2) in a state where at least a part of each other of the layers A and B is mixed is measured. Therefore, the fact that Tg2 is lower than Tg1 means that the Tg of layer A is lower than the Tg of layer B. Tg1-Tg2 is preferably large, more preferably Tg1-Tg2> 2, and even more preferably Tg1-Tg2> 5. Although there is no particular upper limit, 20 is mentioned as an example of the upper limit of Tg1-Tg2 because the stretchability deteriorates when Tg1-Tg2 becomes too large.

The laminated film of the present invention preferably has a breaking elongation of 50% or more in both the main orientation axis direction and the direction perpendicular to the main orientation axis. It is also preferable that the tear propagation resistance in the main orientation axis direction and the direction perpendicular to the main orientation axis is 3 N / mm or more. The projected image display member to which the laminated film of the present invention is applied is often required to have impact resistance and anti-scattering property. These characteristics are especially important for automobile windshields. The impact resistance of the projected image display member to which the laminated film of the present invention is applied when the breaking elongation in both the main orientation axis direction and the direction perpendicular to the main orientation axis of the laminated film of the present invention is 50% or more. And the anti-scattering property can be improved. Further, the same effect can be obtained when the tear propagation resistance in the main orientation axis direction and the direction perpendicular to the main orientation axis is 3 N / mm or more, and it is also a preferable embodiment that both requirements are satisfied at the same time.

Here, the main orientation axis direction can be obtained by using a phase difference measuring device, and as the phase difference measuring device, for example, a phase difference measuring device (KOBRA-21ADH) manufactured by Oji Measuring Instruments Co., Ltd. can be used. it can. The higher the elongation at break in both the main orientation axis direction and the direction perpendicular to the main orientation axis, the more preferable, but the upper limit of the film characteristics is about 300%. Further, the higher the tear propagation resistance in the main orientation axis direction and the direction perpendicular to the main orientation axis, the more preferable, but the upper limit of the film characteristics is about 300 N / mm.

In the laminated film of the present invention, as a method of setting the breaking elongation in both the main orientation axis direction and the direction perpendicular to the main orientation axis to 50% or more, for example, a method of adjusting the resin composition and stretching conditions of the film can be mentioned. .. More specifically, for example, regarding the resin composition, there is a method in which at least one layer of two types of thermoplastic resins laminated alternately is a crystalline resin. Among the crystalline resins, polyester, polyethylene terephthalate and its polymer, polyethylene naphthalate and its copolymer, polybutylene terephthalate and its copolymer, polybutylene naphthalate and its copolymer, and polyhexamethylene terephthalate. And its copolymer, polyhexamethylenenaphthalate and its copolymer, and the like are preferably used. As for the stretching conditions, a method of using the above-mentioned resin, heating the resin at a temperature equal to or higher than the glass transition temperature, and stretching in the biaxial direction perpendicular to each other can be mentioned.

Similarly, the above-mentioned method can be mentioned as a method of setting the tear propagation resistance in the main orientation axis direction and the direction perpendicular to the main orientation axis to 3 N / mm or more, but as a method of further increasing the tear propagation resistance, at least one layer is used. Examples thereof include a method in which a crystalline resin is used as a main component and the other layer is used as a layer containing an amorphous resin as a main component, and a method in which both layers are used as a polyester-based layer. By using a crystalline resin for one layer and an amorphous resin for the other layer, the impact when the laminated film is torn is absorbed by the amorphous resin layer, so that the tear propagation resistance is improved. Further, polyester is a tougher resin than other resins, and by using polyester for both layers, the adhesion between the layers is improved and the tear propagation resistance is improved. Here, the main component means a component contained in 70% by mass or more and 100% by mass or less in 100% by mass of all the components constituting the layer.

The laminated film produced by stretching in only one direction as in Patent Documents 1 and 2 has extremely low mechanical properties in the direction perpendicular to the stretching direction, and both in the main orientation axis direction and in the direction perpendicular to the main orientation axis. It is very difficult to achieve a breaking elongation of 50% or more and a tear propagation resistance of 3 N / mm.

Next, the form of the projected image display member using the laminated film of the present invention will be described. Specific examples include a projected image display member in which the laminated film of the present invention is laminated on at least one surface of the transparent member, and a projected image display member in which the laminated film of the present invention is laminated between two transparent members. Here, examples of the transparent member include glass and resin, and examples of the resin include polyethylene terephthalate, polycarbonate, acrylic, polyvinyl chloride, polyethylene, polypropylene, polymethylpentene and its copolymers, and acrylonitrile-butadiene-styrene copolymers. Can be mentioned.

When laminating the transparent member and the laminated film of the present invention, an adhesive layer may be provided between them, and the adhesive layer is a vinyl acetate resin system, a vinyl chloride / vinyl acetate copolymer system, or an ethylene / vinyl acetate copolymer system. , Polyvinyl alcohol, polyvinyl butyral, polyvinyl acetal, polyvinyl ether, nitrile rubber, styrene / budadiene rubber, natural rubber, chloroprene rubber, polyamide, epoxy resin, polyurethane, acrylic resin, cellulose, polyvinyl chloride Examples thereof include vinyl, polyacrylic acid ester, and polyisobutylene. Further, an adhesiveness adjusting agent, a plasticizer, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, a coloring agent, a cross-linking agent and the like may be added to these adhesives. Examples of the unprocessed form of these adhesive layers include liquid, gel, lump, powder, and film. Examples of the method for solidifying the adhesive layer include solvent volatilization, moisture curing, heat curing, curing agent mixing, anaerobic curing, ultraviolet curing, heat melting and cooling, and pressure sensitivity. Examples of the laminating method include laminating molding and injection molding, and a projected image display member is created by heating, pressurizing, and using the above-mentioned solidification method of the adhesive layer.

Further, on the surface of the projected image display member, a hard coat layer, an abrasion resistant layer, a scratch prevention layer, an antireflection layer, a color correction layer, an ultraviolet absorption layer, a light stabilization layer (HALS), a heat ray absorption layer, a printing layer, and a gas barrier. It may have a functional layer such as a layer, an adhesive layer, and a transparent electrode layer. An automobile windshield is mentioned as a projected image display member in which the laminated film of the present invention is laminated between two transparent members. Examples of the structure include glass / polyvinyl butyral / laminated film of the present invention / polyvinyl butyral / glass structure, in which the glass thickness is in the range of 2 mm to 3 mm and the polyvinyl butyral thickness is in the range of 100 μm to 1000 μm.

The projected image display member of the present invention preferably has an S wave reflectance (Rs70) of 30% or less when it is incident at an incident angle of 70 °. When the projected image display member of the present invention is used as the HUD, it is required that the information display is high and the visibility of external information such as the outside scenery seen through the display unit is also high. Therefore, Rs70 When the value is 30% or less, the visibility of external information such as the outside scenery can be improved. As a method of reducing Rs70 to 30% or less, AR (anti-reflection), AG (anti-glare), a moth-eye structure having a plurality of conical protrusions smaller than the wavelength of visible light is formed on the surface of the projected image display member. To do. Since the inclination angle of the windshield of an automobile is around 70 °, it is particularly preferable that Rs70 is 30% or less when the projected image display member of the present invention is used for the windshield of an automobile.

The projected image display member using the laminated film of the present invention is a projected image display device provided with a light source that irradiates light at an angle of 20 ° or more, preferably 40 ° or more and 75 ° or less with respect to the normal of the display surface. Used for. Such a projected image display device can display information clearly and with high reproducibility while maintaining transparency in the front direction. Examples of the light source include a liquid crystal projector, an RGB laser, DLP (Digital Light Processing), and LCOS (Liquid crystal on silicon). The light (information) emitted from the light source is projected directly onto the projected image display member, reflected by a mirror, condensed through a lens, diffused, and passed through a polarized light reflecting member. It can be projected on. As this mirror, a cold mirror that reflects only visible light is preferable. A mirror that reflects normal visible light to infrared rays reflects the sunlight that has entered the inside of the projected image display device with the mirror and causes the temperature to rise due to infrared rays, but the cold mirror does not reflect infrared rays. Therefore, the temperature rise of the light source can be suppressed. Since the polarized light reflecting member reflects light in one azimuth direction with respect to the surface (reflection axis azimuth) and transmits light in a direction orthogonal to that direction (transmission axis azimuth), it invades from the outside such as sunlight. The light that causes the temperature rise inside the projected image display device can be reduced by about half. On the other hand, by adjusting the polarization of the light from the light source so as to match the transmission axis orientation of the polarization reflecting member, it is possible to suppress the attenuation of the brightness of the light projected from the light source.

The projected image display device using the laminated film of the present invention has a P wave intensity (P wave intensity / (P wave intensity + S wave intensity)) in the intensity of light incident on the display surface of the projected image display member. ) Is preferably 51% or more. One of the problems of AR which is the object of the present invention is the problem of double image of displayed image. This means that light is reflected on each of the front and back surfaces of the image display member, and the light rays are misaligned, so that the displayed image looks double. FIG. 3 shows the difference in the reflection characteristics in the oblique direction between the normal transparent member (the same applies to the reference numeral 2 FIG. 4) and the laminated film of the present invention (the same applies to the reference numeral 3 FIG. 4). In the transparent member, the incident S wave is reflected on the front surface and the back surface of the transparent member, and the P wave is hardly reflected because of the incident angle near the Brewster angle. On the other hand, in the laminated film of the present invention, the incident S wave is reflected on the front surface and the back surface as in the transparent member, and the P wave is reflected by the interference reflection inside the laminated film.

FIG. 4 shows the oblique reflection characteristics of the projected image display member in which the laminated film of the present invention is encapsulated inside the transparent member as an example of the projected image display member of the present invention. As for the incident S wave, reflection occurs on the front surface and the back surface of the projected image display member, so that a double image is generated. On the other hand, for the P wave, the reflection of the front surface and the back surface of the projected image display member is not generated, and only the reflection due to the interference reflection inside the laminated film is generated, so that the double image is not generated. Therefore, regarding the polarization component of the light incident on the display surface of the projected image display member of the present invention, the ratio of the S wave and the P wave decreases as the ratio of the P wave increases. Therefore, when the laminated film of the present invention is used for a projected image display member application, the intensity of the P wave in the intensity of the incident light is more preferably 70% or more, further preferably 80% or more, and particularly preferably 95%. As mentioned above, it is most preferably 99% or more.

Patent Document 1 also describes that the double image (ghost) is reduced by converting the light from the light source to P-polarized light, but the laminated film described in Patent Document 1 is a polarizing reflection film. Therefore, if the azimuth angle of the P-polarized light incident on the laminated film and the azimuth angle of the reflection axis of the polarizing reflection film do not match, the oblique reflectance of the incident light decreases. In particular, when the azimuth angle of the P-polarized light incident on the laminated film and the azimuth angle of the reflection axis of the polarizing reflection film deviate by 90 °, oblique reflection of the incident light does not completely occur. Therefore, there are restrictions on the azimuth angle of the reflection axis of the polarizing reflection film and the position of the light source to be installed. On the other hand, the oblique reflectance of the laminated film of the present invention is hardly affected by the azimuth angle of the P-polarized light incident on the laminated film, so that the position of the light source is not limited. This characteristic is particularly effective when there are a plurality of light sources. Further, it is preferable that the azimuth angle variation of the R70 is 10% or less because the displayability such as the brightness of the information can be maintained at the same level regardless of the direction in which the information is projected.

The projected image display device of the present invention can be used as a head-up display (HUD) or a head-mounted display (HMD) used in automobiles, aircraft, electronic signboards, game machines, and the like. When used in an automobile, information is projected from a small projection substrate toward a windshield of the automobile or a prompter made of a transparent substrate provided near the windshield. Here, by using the laminated film of the present application for the windshield and the prompter, it is possible to display information clearly and with high reproducibility while maintaining transparency in the front direction. In this case, the laminated film may be attached to the windshield via an adhesive, or may be inserted inside the laminated glass used for the windshield. Further, the prompter may also be used in combination with the transparent base material.

In the projected image display device of the present invention, the azimuth angle of the main orientation axis of the laminated film is preferably within ± 30 ° with respect to the floor surface. Here, the azimuth in the horizontal direction with respect to the floor surface is set to 0 °. Generally, light in the natural world is polarized by reflections from buildings and the ground, and is mainly S-polarized. When external information such as an outside landscape passes through the image display device of the present invention, the azimuth angle of the S-polarized light is horizontal with respect to the floor surface. Since the laminated film of the present invention is produced by stretching in at least two directions, it has optical characteristics such as biaxiality and main orientation axis. When the polarized light passes through the laminated film at an azimuth angle larger than 0 with respect to the main orientation axis of the laminated film, the polarization state of the transmitted light changes. That is, when the transmitted polarized light is information such as an outside landscape, unevenness of the rainbow pattern, which is not in the original landscape, may be visually recognized due to a change in the polarization state. This rainbow pattern unevenness has the maximum intensity when the main orientation axis of the laminated film and the azimuth angle of the passed polarized light are 45 °. Therefore, by reducing this azimuth angle, the unevenness of the rainbow pattern can be reduced. The azimuth angle of the main orientation axis of the laminated film is preferably within ± 15 °, more preferably within ± 10 ° with respect to the floor surface. As described above, the projection image display device of the present invention can improve the visibility of external information such as the outside scenery by setting the azimuth angle of the main orientation axis of the laminated film within ± 30 ° with respect to the floor surface. it can. In particular, suppression of this rainbow pattern unevenness is important when the projected image display device of the present invention is applied to the windshield of an automobile.

Next, the head-up display and the head-mounted display of the present invention will be described. The head-up display and head-mounted display of the present invention use a projected image display device. The projected image display device of the present invention is excellent in visibility of information from the outside such as a landscape, displayability of information from a projection member, reproducibility of color, and reduction of distortion by the laminated film of the present invention.

Hereinafter, examples of specific embodiments for producing the laminated film of the present invention will be described below, but the laminated film of the present invention is not construed as being limited to such examples. When the laminated film of the present invention has the above-mentioned laminated film structure, a laminated structure having 50 or more layers can be produced by the following method. The thermoplastic resin is supplied from the extruder A corresponding to the layer A and the extruder B corresponding to the layer B, and the polymer from each flow path is combined with a multi-manifold type feed block which is a known laminating device. It is laminated in 50 layers or more by a method using a square mixer or using only a comb type feed block, and then the melt laminate is melt-extruded into a sheet using a T-shaped base or the like, and then on a casting drum. Examples thereof include a method of cooling and solidifying to obtain an unstretched laminated film. As a method for improving the stacking accuracy of the layer A and the layer B, the methods described in Japanese Patent Application Laid-Open No. 2007-307893, Japanese Patent No. 469910, and Japanese Patent No. 4816419 are preferable. If necessary, it is also preferable to dry the thermoplastic resin used for the layer A and the thermoplastic resin used for the layer B.

Subsequently, the unstretched laminated film is stretched and heat-treated. As the stretching method, a known sequential biaxial stretching method or simultaneous biaxial stretching method is preferable. The stretching temperature is preferably in the range of the glass transition temperature or higher of the unstretched laminated film to the glass transition temperature + 80 ° C. or lower. The draw ratio is preferably in the range of 2 to 8 times in each of the longitudinal direction and the width direction, more preferably in the range of 3 to 6 times, and it is preferable to reduce the difference in draw ratio between the longitudinal direction and the width direction. For stretching in the longitudinal direction, it is preferable to perform stretching by utilizing the speed change between the rolls of the longitudinal stretching machine. Further, for stretching in the width direction, a known tenter method is used. That is, the film is conveyed while being gripped by clips at both ends, and stretched in the width direction by widening the clip spacing at both ends of the film.

Further, it is also preferable to perform simultaneous biaxial stretching for stretching with a tenter. A case where simultaneous biaxial stretching is performed will be described. The unstretched laminated film cast on the cooling roll is guided to the simultaneous biaxial tenter, transported while gripping both ends of the film with clips, and stretched simultaneously and / or stepwise in the longitudinal direction and the width direction. Longitudinal stretching is achieved by increasing the distance between the clips of the tenter, and widthwise stretching is achieved by increasing the distance between the rails on which the clips travel. The tenter clip to be stretched and heat-treated in the present invention is preferably driven by a linear motor method. In addition, there are pantograph method, screw method, etc. Among them, the linear motor method is superior in that the draw ratio can be freely changed because the degree of freedom of each clip is high.

It is also preferable to perform heat treatment after stretching. The heat treatment temperature is preferably carried out in the range of the stretching temperature or higher to the melting point of the thermoplastic resin of layer A of −10 ° C. or lower, and it is also preferable that the heat treatment step is performed in the range of the heat treatment temperature of −30 ° C. or lower after the heat treatment. It is also preferable to shrink (relax) the film in the width direction and / or the longitudinal direction during the heat treatment step or the cooling step in order to reduce the heat shrinkage rate of the film. The rate of relaxation is preferably in the range of 1% to 10%, more preferably in the range of 1 to 5%. Finally, the polyester film of the present invention is produced by winding the film with a winder.

The laminated film thus obtained is a projection image display device provided with a light source that is incident on the laminated film at an angle of 20 ° or more, preferably 40 ° or more and 75 ° or less with respect to the normal of the laminated film surface. It is suitable for. The laminated film has R20 ≤ R40 when the reflectance (%) of each P wave when it is incident at angles of 20 °, 40 °, and 70 ° with respect to the normal of the film surface is R20, R40, and R70. <Since the relationship of R70 is satisfied, high reflection performance is exhibited for light incident on the film surface in an oblique direction. Therefore, when information is projected using a light source that is incident on the laminated film at an angle of 20 ° or more, preferably 40 ° or more and 75 ° or less, a display device having excellent visibility can be obtained. More preferably, the display device is provided with a light source that is incident on the laminated film at an angle of 60 ° or more with respect to the normal of the surface of the laminated film, and particularly preferably is provided with a light source that is incident at an angle of 70 ° or more. It is a display device. As the angle of incidence on the laminated film increases, the reflectance also increases, so that the displayability is improved.

Hereinafter, the laminated film of the present invention will be described with reference to Examples.
[Measurement method of physical properties and evaluation method of effect]
The evaluation method of the characteristic value and the evaluation method of the effect are as follows.

(1) Number of Laminates and Laminated Structure The layered structure of the laminated film is determined by observing a sample whose cross section is cut out using a microtome using a transmission electron microscope (TEM) to determine the number of laminated laminated films and the surface layer. The thickness was confirmed. That is, using a transmission electron microscope H-7100FA (manufactured by Hitachi, Ltd.), a cross-sectional photograph of the film was taken under the condition of an acceleration voltage of 75 kV, and the number of layers was confirmed.

(2) Transmittance of laminated film With the standard configuration (solid-state measurement system) of a spectrophotometer (U-4100 Spectrophotometer) manufactured by Hitachi, Ltd., the transmittance at a wavelength of 450 to 650 nm at an incident angle of θ = 0 ° is 1 nm. The average transmittance was determined by measuring in increments. Measurement conditions: The slit was set to 2 nm (visible) / automatic control (infrared), the gain was set to 2, and the scanning speed was set to 600 nm / min.

(3) Reflectance and saturation of laminated film Attach the angle variable reflector and Grantera polarizer attached to the spectrophotometer (U-4100 Spectrophotometer) manufactured by Hitachi, Ltd., and the incident angles θ = 20 °, 40 °, The reflectances of P and S waves were measured in 1 nm increments in the wavelength range of 450 to 650 nm at 70 °. From the obtained reflectance, Rs70 was determined as the average reflectance of P waves in the wavelength range of 450 nm to 650 nm at incident angles of 20 °, 40 °, and 70 °, with Rp20, Rp40, and Rp70 as the average reflectance of S waves. The inclination directions of 20 °, 40 °, and 70 ° were taken along the main orientation axis of the film. The saturation of the reflected light of the P wave incident at 70 ° is the XYZ value under the C light source using the reflection spectrum of the P wave at θ = 70 °, the spectral distribution of the C light source, and the XYZ system color matching function. , And the saturation C ^* value calculated using the XYZ values. The reflectance variation of Rp70 was obtained from the difference between the maximum value and the minimum value of Rp70 measured at each azimuth angle (0 °, 45 °, 90 °, 135 °) with the orientation of the main orientation axis set to 0 °.

(4) Heat Shrinkage Rate at 150 ° C. for 30 Minutes A sample having a size of 150 mm × 10 mm was cut out in the directions orthogonal to the main orientation axis direction and the main orientation axis direction, and marked in the longitudinal direction of the sample at intervals of 100 mm. The distance between the marks was measured using a universal projector (Model V-16A) manufactured by Nikon Corporation, and the value was taken as A. Next, the sample was suspended in a gear oven under a load of 3 g and left in an atmosphere of 150 ° C. for 30 minutes. Then, after taking out the sample and cooling it, the interval of the marks marked earlier was measured and designated as B. At this time, the heat shrinkage rate was calculated from the following formula. The n number was set to 3, and the average value was obtained, and measurements were performed in each of the film main orientation axis direction and the direction orthogonal to the main orientation axis direction.
Heat shrinkage rate (%) = 100 × (AB) / A.

(5) Phase difference, main orientation axial direction A phase difference measuring device (KOBRA-21ADH) manufactured by Oji Measuring Instruments Co., Ltd. was used. A film sample cut out at 3.5 cm × 3.5 cm was placed in the apparatus, and the phase difference at a wavelength of 590 nm at an incident angle of 0 ° and the direction of the main orientation axis were measured.

(6) Melting point, heat of crystal fusion and glass transition temperature Samples were taken from the laminated film to be measured, and the DSC curve of the measurement sample was measured according to JIS-K-7122 (1987) using differential calorimetry (DSC). In the test, the temperature was raised from 25 ° C. to 300 ° C. at 20 ° C./min, the DSC curve of the measurement sample was measured (1st Run), then rapidly cooled using liquid nitrogen, and then again 20 ° C. from 25 ° C. to 300 ° C. The temperature was raised at / min and the DSC curve of the measurement sample was measured (2nd Run). The melting point was measured from the DSC curve of 1st Run. The glass transition point temperature was Tg1 (° C.) measured from the DSC curve of 1stRun and Tg2 (° C.) measured from the DSC curve of 2ndRun, and the difference Tg1-Tg2 was determined. When there are multiple glass transition temperatures, the highest glass transition temperature is described. The devices and the like used are as follows.
・ Equipment: "EXSTAR DSC6200" manufactured by Seiko Instruments Co., Ltd.
-Data analysis "Muse Standard Analysis software, version 6.1U"
-Sample mass: 5 mg.

(7) Molecular Weight of alkylene glycol The film was dissolved in HFIP-d2 (hexafluoro2-propanol / deuterated product) and 1 HNMR was measured. Regarding the obtained spectrum, when the area of the signal having a peak of 3.8 ppm of chemical shift is S1 and the area of the signal having a peak of 3.9 ppm of chemical shift is S2, S1 / S2 × 44 (44: ethylene glycol). The molecular weight of the alkylene glycol was determined by the formula amount of the repeating unit of.

(8) Method for measuring IV (intrinsic viscosity) It was calculated from the solution viscosity measured using an Ostwald viscometer at a temperature of 25 ° C. after dissolving for 20 minutes at a temperature of 100 ° C. using orthochlorophenol as a solvent.

(9) Appearance Evaluation With respect to the projected image display member installed under the fluorescent lamp, the evaluation portion was visually evaluated from angles of 20 ° and 70 ° with respect to the normal direction of the evaluation portion. The evaluation criteria are as follows.
A: I can't see the unevenness.
B: The unevenness is very slight.
C: Unevenness is visible.

(10) Breaking elongation Based on ASTM-D882 (1999), a sample is cut into a size of width 10 mm × length (measurement direction) 200 mm in each of the main orientation axis direction and the direction perpendicular to the main orientation axis direction. The elongation at break point when pulled at a distance between chucks of 50 mm and a pulling speed of 300 mm / min was measured.

(11) Tear propagation resistance Based on JIS-K7128 (1998), the tear strength was measured and the tear propagation resistance was calculated in each of the main orientation axis direction and the direction perpendicular to the main orientation axis direction of the sample. The number of samples was measured at 3, and the value obtained by dividing the average value of the obtained tear strengths by the average value of the sample thickness was defined as the tear propagation resistance (unit: N / mm).

(Resin used for film)
Resin A: A copolymer of polyethylene terephthalate having IV = 0.67 (polyethylene terephthalate obtained by copolymerizing an isophthalic acid component in an amount of 10 mol% with respect to the entire acid component), a refractive index of 1.57, Tg 75 ° C., and Tm 230 ° C.
Resin B: polyethylene terephthalate with IV = 0.65, refractive index 1.58, Tg 78 ° C, Tm 254 ° C.
Resin C: A polyethylene terephthalate copolymer having IV = 0.67 (polyethylene terephthalate obtained by copolymerizing a 2,6-naphthalenedicarboxylic acid component in an amount of 60 mol% with respect to the entire acid component) having a number average molecular weight of 2000, terephthalic acid, A polyester in which an aromatic ester having a butylene group and an ethylhexyl group is blended in an amount of 10% by weight based on the entire resin. Refractive index 1.62, Tg 90 ° C.
Resin D: A copolymer of polyethylene naphthalate with IV = 0.64 (2,6-naphthalenedicarboxylic acid component 80 mol% with respect to the total acid component, isophthalic acid component 20 mol% with respect to the total acid component, molecular weight 400 Polyethylene naphthalate obtained by copolymerizing 5 mol% of the polyethylene glycol of the above with respect to the entire diol component), a refractive acid of 1.63, Tg 85 ° C., and Tm 215 ° C.
Resin E: A copolymer of polyethylene naphthalate with IV = 0.64 (2,6-naphthalenedicarboxylic acid component 80 mol% with respect to the total acid component, isophthalic acid component 20 mol% with respect to the total acid component, molecular weight 200 Polyethylene naphthalate obtained by copolymerizing 8 mol% of the polyethylene glycol of
Resin F: A copolymer of polyethylene terephthalate having IV = 0.73 (polyethylene terephthalate obtained by copolymerizing a cyclohexanedimethanol component in an amount of 33 mol% with respect to the entire diol component), a refractive index of 1.57, and a Tg of 80 ° C.
Resin G: polyethylene naphthalate with IV = 0.64, refractive index 1.65, Tg 120 ° C, Tm 265 ° C.
Resin H: A copolymer of polyethylene terephthalate having IV = 0.67 (polyethylene terephthalate obtained by copolymerizing a 2,6-naphthalenedicarboxylic acid component in an amount of 50 mol% with respect to the entire acid component), a refractive index of 1.62, and a Tg of 105 ° C.

(Example 1)
Resin A was used as the thermoplastic resin constituting the layer A, and resin C was used as the thermoplastic resin constituting the layer B. Resin A and resin C are each melted at 280 ° C. with an extruder, passed through five FSS type leaf disc filters, and then the discharge ratio (lamination ratio) is resin A / resin C = 1. A 401-layer feed block (201 layers for layer A and 200 layers for layer B) designed so that the reflected wavelength of P waves at an incident angle of 70 ° is in the range of 400 nm to 800 nm while measuring so as to be 5. They were joined alternately. Next, it was supplied to a T-die, formed into a sheet, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatically applied voltage of 8 kV with a wire to obtain an unstretched laminated film. .. This unstretched laminated film is longitudinally stretched at 95 ° C. and a draw ratio of 3.6 times, and both sides of the film are subjected to corona discharge treatment in air, and the treated surfaces of both sides of the film (glass transition temperature is 18 ° C.). A laminate-forming film coating solution composed of (polyester resin) / (polyester resin having a glass transition temperature of 82 ° C.) / silica particles having an average particle size of 100 nm was applied. After that, both ends are guided to a tenter gripped with clips, stretched 3.7 times at 110 ° C., heat-treated at 210 ° C. and relaxed in the width direction by 5%, cooled at 100 ° C., and then 50 μm thick (both). A laminated film having a surface layer thickness of 5 μm) was obtained. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 2)
Resin A was used as the thermoplastic resin constituting the layer A, and resin C was used as the thermoplastic resin constituting the layer B. Resin A and resin C are each melted at 280 ° C. with an extruder, passed through five FSS type leaf disc filters, and then the discharge ratio (lamination ratio) is resin A / resin C = 1. 801 layer feed block (layer A is 401 layers, layer B is 400 layers) designed so that the reflection wavelength of P waves at an incident angle of 70 ° is in the range of 400 nm to 1000 nm while measuring so as to be 5. They were joined alternately. Next, it was supplied to a T-die, formed into a sheet, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatically applied voltage of 8 kV with a wire to obtain an unstretched laminated film. .. This unstretched laminated film is longitudinally stretched at 95 ° C. and a draw ratio of 3.6 times, and both sides of the film are subjected to corona discharge treatment in air, and the treated surfaces of both sides of the film (glass transition temperature is 18 ° C.). A laminate-forming film coating solution composed of (polyester resin) / (polyester resin having a glass transition temperature of 82 ° C.) / silica particles having an average particle size of 100 nm was applied. After that, both ends are guided to a tenter gripped with clips, stretched 3.7 times at 110 ° C., heat-treated at 210 ° C. and relaxed in the width direction by 5%, cooled at 100 ° C., and then 110 μm thick (both). A laminated film having a surface layer thickness of 5 μm) was obtained. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 3)
Resin B was used as the thermoplastic resin constituting the layer A, and resin D was used as the thermoplastic resin constituting the layer B. Resin B and resin D are each melted at 280 ° C. with an extruder, passed through five FSS type leaf disc filters, and then the discharge ratio (lamination ratio) is resin A / resin C = 1. A 401-layer feed block (201 layers for layer A and 200 layers for layer B) designed so that the reflected wavelength of P waves at an incident angle of 70 ° is in the range of 400 nm to 800 nm while measuring so as to be 5. They were joined alternately. Next, it was supplied to a T-die, formed into a sheet, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatically applied voltage of 8 kV with a wire to obtain an unstretched laminated film. .. This unstretched laminated film is longitudinally stretched at 90 ° C. and a draw ratio of 3.3 times, and both sides of the film are subjected to corona discharge treatment in air, and the treated surfaces on both sides of the film (glass transition temperature is 18 ° C.). A laminate-forming film coating solution composed of (polyester resin) / (polyester resin having a glass transition temperature of 82 ° C.) / silica particles having an average particle size of 100 nm was applied. After that, both ends are guided to a tenter gripped with clips, stretched 3.5 times at 100 ° C., heat-treated at 210 ° C. and relaxed in the width direction by 5%, cooled at 100 ° C., and then 50 μm thick (both). A laminated film having a surface layer thickness of 5 μm) was obtained. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 4)
Resin B was used as the thermoplastic resin constituting the layer A, and resin D was used as the thermoplastic resin constituting the layer B. Resin B and resin D are each melted at 280 ° C. with an extruder, passed through five FSS type leaf disc filters, and then the discharge ratio (lamination ratio) is resin A / resin C = 1. 801 layer feed block (layer A is 401 layers, layer B is 400 layers) designed so that the reflection wavelength of P waves at an incident angle of 70 ° is in the range of 400 nm to 1000 nm while measuring so as to be 5. They were joined alternately. Next, it was supplied to a T-die, formed into a sheet, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatically applied voltage of 8 kV with a wire to obtain an unstretched laminated film. .. This unstretched laminated film is longitudinally stretched at 90 ° C. and a draw ratio of 3.3 times, and both sides of the film are subjected to corona discharge treatment in air, and the treated surfaces on both sides of the film (glass transition temperature is 18 ° C.). A laminate-forming film coating solution composed of (polyester resin) / (polyester resin having a glass transition temperature of 82 ° C.) / silica particles having an average particle size of 100 nm was applied. After that, both ends are guided to a tenter that is gripped with clips, stretched laterally at 100 ° C. for 3.5 times, heat-treated at 210 ° C. and relaxed in the width direction by 5%, cooled at 100 ° C., and then thickened to 110 μm (both). A laminated film having a surface layer thickness of 5 μm) was obtained. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 5)
A laminated film having a thickness of 110 μm (thickness of both surface layers of 5 μm) was obtained by the same method as in Example 4 except that 1% relaxation in the width direction was performed. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was prepared by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 6)
Resin B was used as the thermoplastic resin constituting the layer A, and resin E was used as the thermoplastic resin constituting the layer B. Resin B and resin E are each melted at 280 ° C. with an extruder, passed through five FSS type leaf disc filters, and then the discharge ratio (lamination ratio) is resin A / resin C = 1. 801 layer feed block (layer A is 401 layers, layer B is 400 layers) designed so that the reflection wavelength of P waves at an incident angle of 70 ° is in the range of 400 nm to 1000 nm while measuring so as to be 5. They were joined alternately. Next, it was supplied to a T-die, formed into a sheet, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatically applied voltage of 8 kV with a wire to obtain an unstretched laminated film. .. This unstretched laminated film is longitudinally stretched at 100 ° C. and a draw ratio of 3.5 times, and both sides of the film are subjected to corona discharge treatment in air, and the treated surfaces on both sides of the film (glass transition temperature is 18 ° C.). A laminate-forming film coating solution composed of (polyester resin) / (polyester resin having a glass transition temperature of 82 ° C.) / silica particles having an average particle size of 100 nm was applied. After that, both ends are guided to a tenter gripped with clips, stretched 3.7 times at 105 ° C., heat-treated at 210 ° C. and relaxed in the width direction by 5%, cooled at 100 ° C., and then 110 μm thick (both). A laminated film having a surface layer thickness of 5 μm) was obtained. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 7)
A laminated film having a thickness of 110 μm (thickness of both surface layers of 5 μm) was obtained by the same method as in Example 6 except that 1% relaxation in the width direction was performed. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 8)
A laminated film having a thickness of 110 μm (thickness of both surface layers of 5 μm) was obtained by the same method as in Example 7 except that the heat treatment was performed at 200 ° C. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 9)
A laminated film having a thickness of 110 μm (thickness of both surface layers of 5 μm) was obtained by the same method as in Example 8 except that the longitudinal stretching was carried out at a magnification of 3.7 times and the transverse stretching was carried out at a magnification of 4.2 times. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 10)
A laminated film having a thickness of 110 μm (thickness of both surface layers of 5 μm) was obtained by the same method as in Example 6 except that the heat treatment was performed at 220 ° C. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 11)
Resin B was used as the thermoplastic resin constituting the layer A, and resin E was used as the thermoplastic resin constituting the layer B. Resin B and resin E are each melted at 280 ° C. with an extruder, passed through five FSS type leaf disc filters, and then the discharge ratio (lamination ratio) is resin A / resin C = 1. A 351 layer feed block (layer A is 176 layers, layer B is 175 layers) designed so that the reflected wavelength of the P wave at an incident angle of 70 ° is in the range of 300 nm to 650 nm while measuring so as to be 2. They were joined alternately. Next, it was supplied to a T-die, formed into a sheet, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatically applied voltage of 8 kV with a wire to obtain an unstretched laminated film. .. This unstretched laminated film is longitudinally stretched at 100 ° C. and a draw ratio of 3.5 times, and both sides of the film are subjected to corona discharge treatment in air, and the treated surfaces on both sides of the film (glass transition temperature is 18 ° C.). A laminate-forming film coating solution composed of (polyester resin) / (polyester resin having a glass transition temperature of 82 ° C.) / silica particles having an average particle size of 100 nm was applied. After that, both ends are guided to a tenter gripped with clips, stretched 3.7 times at 105 ° C., heat-treated at 210 ° C. and relaxed in the width direction by 1%, cooled at 100 ° C., and then 38 μm in thickness (both). A laminated film having a surface layer thickness of 2.5 μm) was obtained. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 12)
Resin B was used as the thermoplastic resin constituting layer A, and the thickness was 110 μm (thickness of both surface layers was 5 μm) in the same manner as in Example 2 except that heat treatment and 1% width relaxation were performed at 205 ° C. A laminated film was obtained. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Example 13)
A laminated film having a thickness of 102 μm (thickness of both surface layers of 1 μm) was obtained by the same method as in Example 4 except that the thickness of the surface layer was 1 μm. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. Since the thickness of the surface layer of Example 13 was as thin as 1 μm as compared with Example 4, the error of the layer thickness of the layer near the surface layer became large with respect to the design, and the maximum value of the reflectance of the P wave having a wavelength of 450 to 650 nm was reached. The difference between the minimum values became large. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Comparative Example 1)
Resin B was used as the thermoplastic resin. It is melted at 280 ° C. with an extruder, passed through five FSS type leaf disc filters, supplied to a T-die, formed into a sheet, and then surface temperature is applied while applying an electrostatic application voltage of 8 kV with a wire. It was rapidly cooled and solidified on a casting drum kept at 25 ° C. to obtain an unstretched film. This unstretched film is longitudinally stretched at 90 ° C. and a draw ratio of 3.3 times, and both sides of the film are subjected to corona discharge treatment in air, and the treated surfaces of both sides of the film (polyester having a glass transition temperature of 18 ° C.). A laminated film coating solution composed of resin) / (polyester resin having a glass transition temperature of 82 ° C.) / silica particles having an average particle size of 100 nm was applied. Then, the film is guided to a tenter that grips both ends with clips, stretched 3.5 times laterally at 100 ° C., heat-treated at 210 ° C. and relaxed in the width direction by 5%, cooled at 100 ° C., and then a film having a thickness of 50 μm. Got Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150 ° C. A projected image display member was produced by drawing a vacuum for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Comparative Example 2)
A multilayer laminated film having a thickness of 110 μm (thickness of both surface layers of 5 μm) was obtained by the same method as in Example 4 except that the resin F was used as the thermoplastic resin constituting the layer B. Table 1 shows the physical characteristics of the obtained film. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Comparative Example 3)
A laminated film having a thickness of 110 μm (thickness of both surface layers of 5 μm) was obtained by the same method as in Example 4 except that the heat treatment was performed at 235 ° C. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

(Comparative Example 4)
Resin G was used as the thermoplastic resin constituting the layer A, and resin H was used as the thermoplastic resin constituting the layer B. Resin G and resin H are melted at 300 ° C. and 290 ° C., respectively, with an extruder, passed through five FSS type leaf disc filters, and then the discharge ratio (lamination ratio) is resin G / resin H with a gear pump. 801 layer feed block designed so that the reflection wavelength in the main orientation axis direction at an incident angle of 0 ° is in the range of 400 nm to 1000 nm while measuring so that = 1.5 (layer A is 401 layers, layer B). 400 layers) were alternately merged. Next, it was supplied to a T-die, formed into a sheet, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatically applied voltage of 8 kV with a wire to obtain an unstretched laminated film. .. Both sides of this unstretched laminated film are subjected to corona discharge treatment in air, and the treated surfaces on both sides of the film are (polyester resin having a glass transition temperature of 18 ° C.) / (polyester resin having a glass transition temperature of 82 ° C.) / average grains. A laminated film coating liquid composed of silica particles having a diameter of 100 nm was applied. After that, both ends are guided to a tenter gripped with clips, stretched 5 times at 140 ° C., heat-treated at 150 ° C. and relaxed in the width direction by 5%, cooled at 100 ° C., and then thickened to 110 μm (both surface layers). A laminated film having a thickness of 5 μm) was obtained. Using Nisshinbo LAMINATOR 0303S, transparent plate glass with a thickness of 3 mm and 10 cm square is laminated on both sides of the laminated film, and PVB (polyvinyl butyral) with a thickness of 0.7 mm is installed between the laminated film and the transparent plate glass, and the temperature is 150. A projected image display member was produced by applying a vacuum at ° C. for 5 minutes and then pressing for 10 minutes. Table 1 shows the physical characteristics of the obtained film and the appearance evaluation results of the projected image display member. _{Further, a thin film layer of Al 2} O ₃ was formed by vapor deposition as an AR layer on both surfaces of the projected image display member, and a thin film layer of MgF ₂ was further formed on the surface by vapor deposition. Table 2 shows the Rs70 of the projected image display member without the AR layer and the projected image display member with the AR layer.

1: Top view of the laminated film of the present invention 2: Transparent member 3: Laminated film of the present invention

According to the present invention, the transparency in the front direction is excellent, so that information is highly visible from the outside such as a landscape, and the oblique direction is excellent, so that the displayability of information from the projection member and the reproducibility of color are high, and distortion is achieved. It is a laminated film for a projection image display member that suppresses the above. The projected image display device using the laminated film of the present invention can be suitably used for a head-up display (HUD), a head-mounted display (HMD), etc. used in vehicles such as automobiles, aircraft, electronic signboards, game machines, and the like. ..

Claims (18)

A laminated film in which 50 or more layers of different thermoplastic resins are laminated, wherein the laminated film has a transmittance of light incident perpendicularly to the laminated film surface of 50% or more, and the laminated film surface has a transmittance of 50% or more. When the reflectance (%) of each P wave when incident at angles of 20 °, 40 °, and 70 ° with respect to the normal is Rp20, Rp40, and Rp70, the relationship of Rp20≤Rp40 <Rp70 is satisfied. In addition, Rp70 is 30% or more, the saturation of the reflected light of the P wave when incident on the normal of the laminated film surface at an angle of 70 ° is 20 or less, and the main orientation axis of the laminated film. A laminated film for a projected image display member having a heat shrinkage rate of 1% or more and 5% or less when heated at 150 ° C. for 30 minutes in either the direction or the direction orthogonal to the main orientation axis direction. The laminated film for a projected image display member according to claim 1, wherein the laminated film has a phase difference of 2000 nm or less. The invention according to claim 1 or 2, wherein the difference between the maximum value and the minimum value of the reflectance of the P wave having a wavelength of 450 to 650 nm when the P wave is incident at an angle of 70 ° with respect to the normal of the laminated film surface is less than 40%. Laminated film for projected image display members. The laminated film has a structure in which two types of thermoplastic resin layers are alternately laminated, and the resin constituting the layer (layer A) made of the first thermoplastic resin contains crystalline polyester and has a second heat. One of claims 1 to 3 in which the resin constituting the layer (layer B) made of a plastic resin is an amorphous polyester and the difference in in-plane refractive index between the layer A and the layer B is 0.04 or less. The laminated film for the projected image display member described. The laminated film for a projected image display member according to claim 4, wherein the thermoplastic resin constituting the layer B of the laminated film contains a structure derived from an alkylene glycol having a number average molecular weight of 200 or more. The thermoplastic resin constituting the layer B of the laminated film contains a structure derived from two or more kinds of aromatic dicarboxylic acids and two or more kinds of alkyldiols, and is derived from an alkylene glycol having a number average molecular weight of 200 or more. The laminated film for a projected image display member according to claim 4 or 5, which includes a structure. A claim that the 1stRun value Tg1 and the 2ndRun value Tg2 satisfy the relationship of Tg1-Tg2> 0 with respect to the glass transition temperature (Tg) obtained by the following method using the differential scanning calorimetry (DSC) of the laminated film. Item 6. The laminated film for a projected image display member according to any one of Items 1 to 6.
[Measurement conditions for glass transition temperature]
The DSC curve of the measurement sample is measured according to JIS-K-7122 (1987) using differential calorimetry (DSC). In the test, the temperature is raised from 25 ° C. to 300 ° C. at 20 ° C./min, the DSC curve of the measurement sample is measured (1stRun), then rapidly cooled with liquid nitrogen, and again from 25 ° C. to 300 ° C. 20 ° C. The temperature is raised at ° C./min and the DSC curve of the measurement sample is measured (2nd Run). Let the glass transition temperature in the DSC curve of the 1st Run be Tg1 and the glass transition temperature in the DSC curve of the 2nd Run be Tg2. When there are a plurality of glass transition temperatures in the DSC curve, the highest glass transition temperature is Tg1 or Tg2. The laminated film for a projected image display member according to any one of claims 1 to 7, wherein the breaking elongation in both the main orientation axis direction and the direction perpendicular to the main orientation axis is 50% or more. The laminated film for a projected image display member according to any one of claims 1 to 8, wherein the tear propagation resistance in both the main orientation axis direction and the direction perpendicular to the main orientation axis is 3 N / mm or more. The laminated film for a projected image display member according to any one of claims 1 to 9, wherein the azimuth angle variation of Rp70 is 10% or less. A projected image display member in which the laminated film according to any one of claims 1 to 10 is laminated on at least one surface of a transparent member. A projected image display member in which the laminated film according to any one of claims 1 to 10 is laminated between at least two transparent members. The projected image display member according to claim 11 or 12, wherein the reflectance (Rs70) of the S wave when incident at an incident angle of 70 ° is 30% or less. A projected image display device including a light source that irradiates light at an angle of 20 ° or more with respect to the normal of the display surface of the projected image display member according to any one of claims 11 to 13. The projected image display device according to claim 14, wherein the azimuth angle of the main orientation axis of the laminated film is within ± 30 ° with respect to the floor surface. The 14th or 15th claim, wherein the intensity of the P wave (intensity of the P wave / (intensity of the P wave + intensity of the S wave)) in the intensity of the light incident on the display surface of the projected image display member is 51% or more. Projection image display device. A head-up display using the projected image display device according to claim 16. A head-mounted display using the projected image display device according to claim 16.

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