WO2010113741A1 - 異方性光拡散フィルム、その積層シート及びその製造方法 - Google Patents

異方性光拡散フィルム、その積層シート及びその製造方法 Download PDF

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WO2010113741A1
WO2010113741A1 PCT/JP2010/055175 JP2010055175W WO2010113741A1 WO 2010113741 A1 WO2010113741 A1 WO 2010113741A1 JP 2010055175 W JP2010055175 W JP 2010055175W WO 2010113741 A1 WO2010113741 A1 WO 2010113741A1
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light
film
anisotropic
anisotropic light
diffusion film
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PCT/JP2010/055175
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English (en)
French (fr)
Japanese (ja)
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勝朗 久世
兼次 河井
一元 今井
章文 安井
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東洋紡績株式会社
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Priority to JP2011507122A priority Critical patent/JP5429284B2/ja
Publication of WO2010113741A1 publication Critical patent/WO2010113741A1/ja

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/07—Flat, e.g. panels
    • B29C48/08—Flat, e.g. panels flexible, e.g. films
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/304—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B32B27/322—Layered products comprising a layer of synthetic resin comprising polyolefins comprising halogenated polyolefins, e.g. PTFE
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/0236—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/0257—Diffusing elements; Afocal elements characterised by the diffusing properties creating an anisotropic diffusion characteristic, i.e. distributing output differently in two perpendicular axes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
    • B29C48/911—Cooling
    • B29C48/9135—Cooling of flat articles, e.g. using specially adapted supporting means
    • B29C48/914—Cooling of flat articles, e.g. using specially adapted supporting means cooling drums
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
    • B29C48/911—Cooling
    • B29C48/9135—Cooling of flat articles, e.g. using specially adapted supporting means
    • B29C48/915—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means
    • B29C48/916—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means using vacuum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
    • B29C48/911—Cooling
    • B29C48/9135—Cooling of flat articles, e.g. using specially adapted supporting means
    • B29C48/915—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means
    • B29C48/9165—Electrostatic pinning
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
    • B29C48/911—Cooling
    • B29C48/9135—Cooling of flat articles, e.g. using specially adapted supporting means
    • B29C48/915—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means
    • B29C48/917—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means by applying pressurised gas to the surface of the flat article
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2270/00—Resin or rubber layer containing a blend of at least two different polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/706—Anisotropic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2551/00—Optical elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2590/00—Signboards, advertising panels, road signs

Definitions

  • the present invention relates to an anisotropic light diffusing film, a laminated sheet thereof, and a manufacturing method thereof. Specifically, the present invention relates to an anisotropic light diffusing film having a so-called anisotropic light diffusing function, excellent in light transmittance and diffusivity, and condensing and diffusing light in a specific direction, a laminated sheet thereof, and a manufacturing method thereof. .
  • LEDs light emitting diodes
  • the light emitted from the LED light source has high straightness (directivity), it is possible to efficiently illuminate a spot-like narrow area, but the light diffusibility is insufficient. Therefore, in order to illuminate a wide area using a large number of light sources, the individual light sources are arranged in a spot shape, and in order to obtain uniform brightness, increase the number of light sources in a dense state. It is necessary to install.
  • the edge light method when illuminating the display using the edge light method, it is necessary to increase the number of LED light sources in order to obtain uniform brightness, and thus the feature of energy saving cannot be effectively utilized.
  • an anisotropic light diffusive film that diffuses light in a specific direction is installed in the light output part of the light source so that the light diffusion direction is diffused in the longitudinal direction of the edge light, the dotted light is elongated in the longitudinal direction of the edge light. Therefore, the number of LED light sources can be greatly reduced.
  • LED lighting is also used as a light source for advertising media and illumination.
  • a film having anisotropic light diffusibility is desired in order to enhance decorativeness and electrical decoration.
  • a plate having at least one primary light source, a light incident end surface on which light emitted from the primary light source is incident and on which light emitted from the primary light source is incident, and a light emitting surface on which the guided light is emitted
  • the light guide body includes a light emission mechanism on both or one of the light emission surface and the opposite back surface, and both or one of the light emission surface and the back surface.
  • At least one local lens array forming portion, and each of the local lens array forming portions includes at least one local lens array, and the local lens array is emitted from the primary light source and formed on the light incident end surface.
  • the incident light it is formed in a direction different from the direction of the peak light in the luminance distribution at the incident position of the maximum intensity light, and a method for eliminating luminance non-uniformity by this is disclosed (Patent Document) Reference 1).
  • a lamp housing having a light source housing portion whose opening is formed at one end and whose inner wall is a light reflecting surface, a light emitting diode provided in the light source housing portion, and a display plate provided in front of the opening portion And a technology for making the light from the light-emitting diode uniform by diffuse reflection (see Patent Document 2).
  • a light source that emits light, an optically transparent light guide that propagates light from the light source and has a radiation surface at a predetermined position in the radiation direction, and a surface other than the radiation surface of the light guide
  • a surface illumination light source including radiation side reflection means provided on the radiation surface and configured to reflect light from the light source at a predetermined ratio
  • Patent Documents 1 to 3 have a problem that the structure of the light source is complicated and inferior in economic efficiency. Moreover, although it can respond to planar illumination, for example, it has the subject that it is difficult to respond as a tubular illumination body such as a fluorescent lamp.
  • various anisotropic light diffusion films have been disclosed in order to improve the uniformity of luminance of a display using a cold cathode tube as a light source.
  • a method of uniaxially stretching a polyester resin see Patent Document 4 (Japanese Patent Laid-Open No. 2000-47009)
  • a method of melt-extrusion of an incompatible thermoplastic resin for example, see Patent Document 5
  • a film A method of controlling the surface shape by performing a shaping process such as embossing on the surface is disclosed.
  • the LED light source has a problem that the light intensity around the light source is increased without the disappearance of the spot of the light source because the directivity of light is strong (hereinafter sometimes referred to as spot disappearance).
  • spot disappearance the light amount of the entire lighting device
  • An anisotropic light diffusing film obtained by a conventionally known method does not satisfy any of the above characteristics and does not satisfy market demand.
  • the diffuse transmittance is 20 to 70%.
  • the method described in Patent Document 5 has a low haze and a spot. It is predicted that the disappearance will be inferior.
  • LCDs liquid crystal display devices
  • PDAs personal digital assistants
  • LCDs liquid crystal display devices
  • the liquid crystal display device is equipped with a backlight unit on the lower surface side of the liquid crystal layer in order to suppress loss in the light transmission path from the light source to the panel and improve the brightness on the panel.
  • a backlight unit on the lower surface side of the liquid crystal layer in order to suppress loss in the light transmission path from the light source to the panel and improve the brightness on the panel.
  • those that emit light by illuminating a liquid crystal layer from the back are widespread, but are roughly classified into a side type and a direct type depending on the arrangement of light sources.
  • backlight units have been used not only in liquid crystal display devices but also in a wide range of fields such as lamps and electric signboards.
  • various optical films such as a backlight, a lens film, a light diffusion film, and a brightness enhancement film and optical members such as a diffusion plate are combined to improve the brightness on the panel and the uniformity of the brightness. It is illustrated. Usually, 2 to 4 members are used (see, for example, Non-Patent Document 1).
  • a lens film for improving luminance is disclosed (for example, see Patent Document 6). Since this method uses the light condensing effect of the lens to improve the luminance, it can improve the luminance when viewed from the front, but the luminance when viewed from the diagonal is viewed from the front. Compared to the brightness of It is also expensive.
  • the single lens film has insufficient luminance uniformity, and a technique of combining the lens film with an anisotropic light diffusion film is disclosed (see Patent Document 8).
  • Patent Document 10 Japanese Patent Document 10
  • Patent Document 12 Japanese Patent Document 10
  • the film described in Patent Document 12 has a low diffusivity and insufficient in-plane luminance uniformity, pattern concealment, and the like.
  • An object of the present invention is to solve the above-described problems in the prior art, and has a so-called anisotropic light diffusion function that excels in light transmittance and diffusivity and condenses and diffuses light in a specific direction.
  • An anisotropic light diffusing film, a laminated sheet thereof, and a manufacturing method thereof are provided.
  • the present invention has been made in view of the above situation, and was able to solve the above problems.
  • the inventors of the present invention are able to suppress the reduction of the total light amount as much as possible from a light source with high straightness of light such as an LED light source, and have a high degree of diffusibility and uniform illumination over a wide range, and further in a specific direction.
  • a light source with high straightness of light such as an LED light source
  • the inventors of the present invention have made extensive studies on anisotropic light diffusing films that are superior in luminance characteristics, the number of sheets used, and the like as compared with the case where conventionally known light diffusing films and lens films are used.
  • An anisotropic light-diffusion film, its lamination sheet, and a manufacturing method consist of the following structures.
  • An anisotropic light diffusing film comprising a mixture of at least two incompatible thermoplastic resins and simultaneously satisfying the following characteristics (1) to (4): (1) The total light transmittance is 66% or more. (2) Haze is over 80%. (3) The parallel light transmittance is less than 20%. (4) The diffusivity ratio 1 (DH1 / DL1) or diffusivity ratio 2 (DH2 / DL2) of the transmitted light measured at an incident angle of 0 degree with a goniophotometer measured by the method described in the specification Either one exceeds 2.0.
  • DH1 and DL1 are the angle width (half width) at half the height of the peak of the variable light curve of the transmitted light measured with an automatic variable photometer, and the winding direction of the anisotropic light diffusion film. Measured by fixing in the vertical and horizontal directions, the larger half-value width is DH1 and the smaller half-width is DL1, and DH2 and DL2 are the variable-angle curve of transmitted light measured by an automatic variable-angle photometer. The frequency of the angle between the peak rising angle and the peak ending angle is measured with the winding direction of the anisotropic light diffusing film fixed in the vertical direction and the horizontal direction. DL2 is the one with the smaller angle.
  • the inflection degree of the light in the main diffusion direction obtained by measuring the winding direction of the light diffusion film in a direction parallel to the vertical direction of the sample fixing base and the horizontal direction is measured. 3.
  • the main component of the mixture of at least two incompatible thermoplastic resins is a mixture in which the blending ratio of the cyclic polyolefin resin and the polyethylene resin is 10/90 to 90/10.
  • Said 5 or 6 characterized in that a surface layer mainly made of polyolefin resin is laminated on at least one surface of a light diffusion film made of a mixture of said at least two incompatible thermoplastic resins. Anisotropic light diffusion film.
  • thermoplastic resin is made of a fluororesin.
  • thermoplastic resin comprises a polyester resin
  • An anisotropic light diffusing film laminate comprising the light diffusing film according to any one of 1 to 12 above and a plastic sheet having a thickness of 0.1 to 5 mm and a total light transmittance of 70 to 100%. Sheet.
  • a lighting illumination apparatus equipped with an LED light source wherein the anisotropic light diffusing film according to any one of 1 to 12 is attached to an outer surface or an inner surface of a light emitting part of the lighting apparatus equipped with the LED light source.
  • a lighting device equipped with an LED light source wherein the anisotropic light diffusion film laminated sheet described in 13 is attached to an outer surface or an inner surface of a light emitting portion of the lighting device equipped with the LED light source.
  • a backlight device wherein the anisotropic light diffusing film according to any one of 1 to 12 is installed on an outgoing light surface of a backlight unit.
  • a backlight device comprising the anisotropic light diffusing film laminated sheet described in 13 above disposed on the outgoing light surface of a backlight unit.
  • the resin melted by an extruder is extruded into a sheet form from a die, and the sheet is formed into a film by being cooled and solidified by adhering the sheet by a gas pressure method and / or suction method and / or electrostatic adhesion method.
  • the anisotropic light diffusing film and laminated sheet of the present invention have a so-called anisotropic light diffusing function that is excellent in light transmittance and diffusivity and condenses and diffuses light in a specific direction, so that the LED light source is strong straight ahead Therefore, even when the number of LED light sources is reduced, uniform illumination can be achieved, for example, when linear illumination is required.
  • it when used as a light source for advertising media, illumination, etc., it has a feature that it can enhance decorativeness and electrical decoration.
  • the transmittance of light traveling straight is small, when used for an illuminating device using an LED light source, the light source spot of strong light is made invisible, and the degree of decrease in the transmittance of the light beam is further reduced.
  • the anisotropic light-diffusion film lamination sheet for illuminating devices using the LED light source of this invention can improve non-optical characteristics, such as heat resistance and intensity
  • the anisotropic light diffusion film of the present invention has an anisotropic light diffusion function and has a higher diffusibility than a conventionally known anisotropic light diffusion film, so when used as a diffusion film of a light guide plate type display. It has the feature that the brightness improvement effect is larger than that.
  • the anisotropic light diffusing film of the present invention and the laminated sheet using the same when used as an optical member of a backlight device, have high brightness, reduced angle dependence of brightness, and in-plane brightness uniformity when used as an optical member of a backlight device. Since it is possible to impart optical characteristics that are necessary as an optical member for the backlight device, such as the property and the pattern concealing property, it is possible to improve the economic efficiency of the backlight device.
  • the backlight device of the present invention has a high front luminance close to that of a backlight device using a lens film, and the angle dependency of luminance, which is a problem of the backlight device using a lens film, is reduced. Therefore, for example, when used in a large TV, there is an advantage that a decrease in the brightness of the screen when viewed obliquely is suppressed.
  • this feature for example, it is useful as a backlight device of a display that is often viewed from an oblique direction such as car navigation.
  • the backlight device of the present invention when used with a backlight device for a lamp for indoor or in-house lighting, there is an advantage that uniform illuminance can be obtained over a wide range as compared with a backlight device using a lens film. Furthermore, the backlight device of the present invention has the advantage that it is highly economical because all of the above characteristics can be imparted by using a single member. Therefore, the backlight device of the present invention can be effectively used in a liquid crystal display device, indoor lighting, an interior illumination panel, and the like. Moreover, according to the method for producing an anisotropic light diffusing film of the present invention, the anisotropic light diffusing film of the present invention having the above characteristics can be produced economically and stably.
  • the auxiliary figure of a diffusivity calculation method The auxiliary figure of the inflection degree calculation method.
  • the anisotropic light diffusion film of the present invention (hereinafter sometimes simply referred to as a light diffusion film)
  • An anisotropic light diffusing film comprising a mixture of at least two incompatible thermoplastic resins and simultaneously satisfying the following characteristics (1) to (4): (1) The total light transmittance is 66% or more. (2) Haze is over 80%. (3) The parallel light transmittance is less than 20%. (4) The diffusivity ratio 1 (DH1 / DL1) or diffusivity ratio 2 (DH2 / DL2) of the transmitted light measured at an incident angle of 0 degree with a goniophotometer measured by the method described in the specification Either one exceeds 2.0.
  • the angle width (half width) at half the height of the peak of the variable light curve of transmitted light measured with an automatic variable photometer is perpendicular to the winding direction of the light diffusion film. Measurement is performed with the direction and the horizontal direction fixed, and the larger half width is DH1, and the smaller half width is DL1. Further, DH2 and DL2 are the degrees of the angle between the rising angle and the ending angle of the peak of the variable angle luminous intensity curve of the transmitted light measured with an automatic variable angle photometer, and the winding direction of the light diffusion film is vertical and The measurement is carried out while fixing in the horizontal direction, and the greater angle power is DH2, and the smaller angle power is DL2. )
  • the direction of DH may be referred to as the main diffusion direction.
  • the total light transmittance is more preferably 68% or more, and still more preferably 70% or more. 80% or more is particularly preferable. Note that 100% is the upper limit because there is no principle that it exceeds 100%. Since it is preferable that the total light transmittance is higher, it is more preferably 90% or more, and most preferably 100%. However, a loss may occur due to reflection at the interface, and the upper limit is practically 98%. Furthermore, it may be about 95% and about 93% when there is a lot of loss. If the light transmittance is less than 66%, for example, the transmittance of light emitted from the LED light source is decreased, and the amount of light when used as illumination is decreased, so that the illuminance and luminance of the illumination device are decreased.
  • the parallel light transmittance is more preferably 10% or less, further preferably 5% or less, and still more preferably 2% or less. In addition, since it is not theoretically less than 0%, 0% is a lower limit. When the parallel light transmittance exceeds 20%, for example, the spot disappearance of the LED light source is deteriorated, and the amount of light in the spot due to the strong light of the light source is increased, so that uniform illumination cannot be obtained.
  • the haze of the film is preferably more than 80%.
  • the haze is preferably 90% or more, more preferably 95% or more, and still more preferably 97% or more. Note that 100% is the upper limit because there is no principle that it exceeds 100%. If the haze is less than 80%, the light diffusibility is lowered, and uniform illumination over a wide range cannot be achieved. In order to perform uniform illumination over a wide range, it is necessary to increase the number of LED light sources, which is economically disadvantageous. In addition, it is necessary to increase the distance between the light source and the anisotropic light diffusing film, which limits the thinning of the lighting device.
  • either one of the diffusivity ratio 1 (DH1 / DL1) or the diffusivity ratio 2 (DH2 / DL2) of the transmitted light measured by the following method exceeds 2.0 (however, DH1 and DL2 are the angle width (half width) at half the height of the peak of the variable light curve of transmitted light measured with an automatic variable photometer, and the winding direction of the light diffusion film is vertical and horizontal. DH1 and DL2 are the ones with the larger half-value width, DL1 and DH2 and DL2 are the rises in the peak of the variable light curve of the transmitted light measured with an automatic variable angle photometer.
  • the power of the angle between the angle and the end angle of the peak is measured by fixing the winding direction of the anisotropic light diffusion film in the vertical direction and the horizontal direction, and the larger power of the angle is DH2, and the power of the angle The smaller of D 2 to.)
  • either diffusivity ratio 1 or 2 only needs to exceed 2.0, but it is more preferable that both exceed 2.0 because the degree of anisotropy is further improved. That is, when either diffusivity ratio 1 or diffusivity ratio 2 (DH2 / DL2) in the present invention exceeds 2.0, at least either diffusivity ratio 1 or 2 exceeds 2.0. The state where both are over 2.0 is the preferred state.
  • Both the diffusivity ratio 1 (DH1 / DL1) and the diffusivity ratio 2 (DH2 / DL2) are indexes representing the anisotropy of light.
  • a diffusivity ratio of 1 has been used as a measure of anisotropy of light diffusion.
  • films that exhibit strong light diffusion anisotropy even when the diffusivity ratio is less than 2.0 As a result of intensive studies on the light diffusion characteristics of the film, diffusion is a measure of the anisotropy of the diffusion film. It was found that the degree ratio 2 is also important. That is, in solving the problem, it is necessary to consider not only the half-width range where the light amount is relatively large but also the angle at which the light spreads in the portion where the light amount is low.
  • either diffusivity ratio 1 or 2 is preferably 2.5 or more, and more preferably 3.0 or more.
  • both diffusivity ratios 1 and 2 are 2.0 or less, the light diffusion anisotropy is low, the degree of light condensing in a specific direction is low, and the light diffusion anisotropy is lowered, which is not preferable.
  • the upper limit is not limited, practically, about 20 or about 15 is a preferable range for both diffusivity ratios 1 and 2.
  • the LED light source when the LED light source is arranged in a line in the case where the main diffusion direction of the anisotropic light diffusion film is arranged in a direction orthogonal to the LED light source arrangement direction, The light can be converted into a linear uniform band of light in the arrangement direction of the LED light sources.
  • the film when the film is used so that the main diffusion direction is parallel to the LED light source arrangement direction, the light from the LED light source that is dotted is only emitted in the direction orthogonal to the arrangement direction of the LED light sources. Can be concentrated and diffused.
  • the parallel light transmittance, haze, and diffusivity are set in appropriate ranges, the visibility of the spot of the LED light source is reduced, and the glare of the LED light source is suppressed.
  • the luminance when used in a backlight device, there are cases where the luminance can be improved by improving the light condensing property as compared with the isotropic light diffusion film.
  • the diffusivity ratio is obtained by measurement by the following method.
  • GP-200 manufactured by Murakami Color Research Co., Ltd.
  • the width (half width) of the angle at the half height of the peak height of the obtained variable angle luminous intensity curve of the transmitted light was obtained.
  • the above measurement was carried out with the winding direction of the anisotropic light diffusion film fixed in the vertical direction and the horizontal direction, and the diffusivity ratio 1 (DH1 / DL1) was determined with DH1 as the larger half width and DL1 as the smaller half width.
  • the diffusivity ratio 2 (DH2 / DL2) was obtained by setting DH2 as the greater frequency of the angle between the peak rising angle and the peak ending angle and DL2 as the smaller frequency (see FIG. 1).
  • the portion was observed with a magnifying glass 10 times, and the most advanced angle where the line of the peak disappeared was defined as each angle. A clear determination can be made if this is done.
  • the measurement when there was a difference in the surface roughness of the light diffusing film, the measurement was performed by fixing the light diffusing film in the direction in which light passes when actually used. The surface on which the light receiver is moved is defined as the equator plane.
  • the DH2 is preferably 110 degrees or more. 120 degree
  • an anisotropic light diffusing film having the above characteristics is used for a backlight device, and in order to effectively exhibit the effects of the present invention, the inflection degree of light measured by the following method is 4 ⁇ 100% is preferred.
  • the inflection degree of light in the present invention is obtained by measurement by the following method. ⁇ Measurement method of light inflection> Measurement is performed using an automatic variable angle photometer (GP-200: manufactured by Murakami Color Research Co., Ltd.).
  • Transmission measurement mode light incident angle: 0 ° (angles perpendicular to the sample surface, both right and left, right and left), light receiving angle: -90 ° to 90 ° (angle on the equator plane), filter: ND10 used, beam stop 10.5 mm (VS-1 3.0), light-receiving aperture: 9.1 mm (VS-3 4.0), and measurement with a variable angle interval of 0.1 degree.
  • the measurement was performed by changing the settings of SENSITIVITY and HIGH VOLTON so that the ratio was 40 to 90%.
  • the height (H0) at an angle of 0 degree of the variable angle luminous intensity curve of the obtained transmitted light is obtained.
  • the height (H60) at an angle 0 degree of the variable light intensity curve of the transmitted light when measured under the same conditions as described above is obtained.
  • the surface on which the light receiver is moved is defined as the equator plane.
  • the inflection degree of the light is obtained by measuring in the main diffusion direction. When there is a difference in the surface roughness of the anisotropic light diffusing film, the above measurement is performed by fixing in the direction in which light passes in the same direction as when actually used in the backlight device.
  • the inflection degree of the light is more preferably 6% or more, and further preferably 8% or more.
  • the upper limit of the inflection is preferably 100%, but in reality, it is 80% or less, further 70%, particularly 60% or less, and in some cases 55% or less. If the inflection of light is less than 4%, when only one anisotropic light diffusing film is used as an optical member for a backlight device, optical properties for the backlight device such as high luminance and reduction of the angle dependency of luminance are provided. Since it may become impossible to give the optical characteristic which needs to be provided as a member, it is not preferable.
  • the characteristic is a scale indicating, for example, the degree of the light inflection effect in the film when the light is incident on the anisotropic light diffusing film, that is, the degree that the light incident at a high angle is emitted toward the front. It is. In a sense, it can be regarded as a measure of the light collection effect.
  • the light diffusion film of the present invention has a larger inflection effect than conventionally known light diffusion films and lens films. Therefore, it is presumed that the above effects of the present invention can be efficiently expressed.
  • the anisotropic light diffusing film of the present invention when used in a backlight device for a liquid crystal display, even if only one sheet is used, the angle dependency of luminance is reduced, the in-plane luminance uniformity is improved, and the pattern concealing property is improved.
  • Various characteristics can be satisfied. Conventionally, a lens film film, a light diffusing film (sheet), and a light diffusing plate are used, and only one part of the above characteristics can be satisfied in the use of each member. Even so, providing the ideal characteristic that all the characteristics can be satisfied at the same time is the first time that the anisotropic light diffusion film of the present invention can be achieved.
  • the ideal characteristics can be imparted by satisfying the above-mentioned plurality of optical characteristics simultaneously. For example, it is speculated that a high degree of light inflection contributes to in-plane luminance homogeneity and pattern concealment when a high degree of diffusion is related to the angle dependence of luminance.
  • the anisotropic light diffusing film of the present invention is preferably composed of a mixture of at least two incompatible thermoplastic resins.
  • the presence form of the mixture of the at least two incompatible thermoplastic resins is not particularly limited as long as the optical characteristics are satisfied.
  • a so-called sea / island structure in which each resin exists independently as a continuous phase and a dispersed phase may be used, or a structure in which both resins form a co-continuous phase may be used.
  • the above characteristics are imparted by light refraction and scattering at the interface between the two resins.
  • thermoplastic resin used in the mixture of at least two incompatible thermoplastic resins in the present invention examples include polyethylene resins, polypropylene resins, polybutene resins, cyclic polyolefin resins, and the like.
  • examples thereof include polyolefin resins such as polymethylpentene resins, polyester resins, acrylic resins, polystyrene resins, polycarbonate resins, fluorine resins, and copolymers thereof.
  • at least two types may be selected from these thermoplastic resins, polyolefin resins, polyester resins, fluorine resins, and the like are preferable as the other resins of the two types of resins. It is appropriately selected in consideration of optical characteristics, other required characteristics, economy, and the like.
  • the blending ratio of the at least two incompatible thermoplastic resins is preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and more preferably 30/70 to 30/70, respectively.
  • the ratio of 70/30 is more preferable, it largely varies depending on the kind of the resin component and the layer configuration described later, the thickness of the light diffusion layer, the manufacturing method, and the like. Generally speaking, the more the mass ratio is away from 50/50, the more the number of interfaces between the two incompatible thermoplastic resins decreases, so the total light transmittance decreases, the haze decreases, and the parallel light transmittance increases. is there.
  • melt flow rate of the island component when the melt flow rate of the island component is low, it becomes difficult to apply a force to thin the island component due to the share or draft in the die and the anisotropy may be reduced, but the mass ratio is 50/50. This tendency becomes stronger as you move away from. Each characteristic can be adjusted in consideration of these tendencies.
  • melt flow rate when the melt flow rate is close, it is necessary to take into account that the components of the sea-island structure are reversed depending on the ratio.
  • the above resin may be selected from commercially available resins having high versatility, but a custom-made product may be used for measures such as more stable production. Polyester resins are easy to achieve the above optical characteristics and are excellent in mechanical characteristics and thermal characteristics other than optical characteristics. Preference is given to using copolymers and / or copolymers. It is also economically advantageous.
  • a polyolefin resin described later is preferable.
  • the fluorine-based resin is not limited as long as it satisfies the above characteristics. It is preferable to use a copolymer with an olefin monomer such as ethylene or propylene.
  • the fluororesin is excellent in light resistance. For example, an anisotropic light diffusion film excellent in light resistance can be obtained by combining with a polyolefin resin.
  • a polyolefin resin described later is preferable.
  • At least one type is made of a polyolefin-based resin from the viewpoint that the above characteristics can be stably expressed, in particular, from the point of satisfying the contradictory phenomenon of coexistence of total light transmittance and haze, parallel light transmittance and diffusivity ratio. It is preferable.
  • the polyolefin resin include polyethylene, polypropylene, polybutene, potipentene, polyhexene, polymethylpentene, copolymers thereof, cyclic polyolefin, and the like.
  • the combination is not particularly limited, but the difference in refractive index between the two types of polyolefin resins is preferably in the range of 0.003 to 0.07.
  • the range of 0.005 to 0.05 is more preferred, and 0.01 to 0.02 is even more preferred.
  • the refractive index of the island phase is preferably higher than the refractive index of the sea phase for stable production.
  • a combination of a cyclic polyolefin resin and a polyethylene resin is preferable in that the above-mentioned optical characteristics, in particular, the above-mentioned anti-twisting characteristics can be achieved stably. It is also economical.
  • cyclic polyolefin-based resin examples include those having a cyclic polyolefin structure such as norbornene and tetracyclododecene. These can increase the glass transition temperature, and it is considered that the island components thinned by the shear and draft in the die are solidified quickly during cooling, and stable characteristics are easily obtained.
  • the glass transition temperature is preferably 100 ° C or higher, more preferably 110 ° C or higher, and particularly preferably 120 ° C or higher.
  • the upper limit is naturally determined by the monomer type (Tg of 100% cyclic monomer), but is preferably 230 ° C. or lower, more preferably 200 ° C. or lower, and particularly preferably 190 ° C. or lower.
  • the values are values measured at a heating rate of 10 ° C./min in accordance with ISO11357-1, -2, -3.
  • Examples of the cyclic polyolefin-based resin include: (1) a ring-opening (co) polymer of a norbornene-based monomer, which is subjected to polymer modification such as maleic acid addition and cyclopentadiene addition as necessary, and then hydrogenated resin; (2) Resin obtained by addition polymerization of norbornene monomer and (3) Resin obtained by addition copolymerization with norbornene monomer and olefin monomer such as ethylene and ⁇ -olefin.
  • the polymerization method and the hydrogenation method can be performed by conventional methods.
  • the content of the cyclic component of the cyclic polyolefin resin is preferably 70 to 90% by mass, more preferably 73 to 85% by mass.
  • a cyclic polyolefin resin copolymerized with ethylene is preferable in order to achieve high properties with high affinity with a polyethylene resin.
  • the ethylene content is preferably 30-10% by mass, more preferably 27-15% by mass.
  • the polyethylene resin may be a single polymer or a copolymer. In the case of a copolymer, it is preferable that 50 mol% or more is an ethylene component.
  • the density and polymerization method of the resin are not limited, but it is preferable to use a copolymer having a density of 0.909 or less. Examples thereof include copolymers with propylene, butene, hexene, octene and the like.
  • the polymerization method may be either a metallocene catalyst method or a nonmetallocene catalyst method. In particular, the use of a block copolymer of ethylene and octene is preferred in that high diffusibility can be stably imparted.
  • the resin may include INFUSE (TM) manufactured by Dow Chemical Company. Since the resin has a crystalline part because of the block structure, it has a feature that it has a low melting point and a high melting point, and is preferable because it can improve the heat resistance and the like of the obtained anisotropic light diffusion film. .
  • the cyclic polyolefin resin is preferably blended in an amount of 10 to 60% by mass, more preferably 10 to 50% by mass in the total resin amount.
  • This range is preferable for realizing a preferred embodiment in which a polyethylene resin described later is used as the sea phase.
  • the melt flow rate of the thermoplastic resin used as the at least two incompatible thermoplastic resins is preferably different from the melt flow rate of each thermoplastic resin.
  • the melt flow rate of the resin is appropriately selected in consideration of the resin composition, composition ratio, which resin is used as the sea, desired optical characteristics, and the like.
  • a simple sea / island structure may be formed instead of a co-continuous phase, for example.
  • the polyethylene resin is used as the sea phase, and the melt flow rate of the polyethylene resin of the sea phase is set higher than the melt flow rate of the cyclic polyolefin resin of the island phase.
  • the desired optical properties, particularly the diffusivity ratio are related to the share in the die, the flexibility and fluidity of the sea phase. It is difficult to obtain a high anisotropic light diffusion film.
  • an anisotropic light diffusing film having a desired optical characteristic, particularly a high diffusivity ratio can be obtained stably.
  • the optical characteristics of the anisotropic light diffusing film obtained may not be reproduced even if the same resin composition is formed under the same conditions by changing the film forming apparatus.
  • the present invention has been intensively studied to find a solution to this problem.
  • the above problem is likely to occur when a cyclic polyolefin resin having a configuration opposite to the above configuration is used as the sea phase. The reason for this is not clear, but even if there is a change in the share etc. due to the difference in extrusion conditions and die shape that occurs when the film forming apparatus is changed, the sea phase resin is made softer than the island phase resin, and It is presumed that the effect is mitigated by increasing the liquidity.
  • the polyolefin resin when used as the mixture of the at least two incompatible thermoplastic resins, at least one side of the layer composed of the mixture of at least two polyolefin resins is used. It is a preferable embodiment that a surface layer mainly made of polyolefin resin is laminated.
  • a layer made of a mixture of at least two types of polyolefin resins may be referred to as a light diffusion layer.
  • the polyolefin resin used for forming the surface layer it is preferable to use a crystalline resin in order to develop an effect such as suppression of blocking property.
  • a polyolefin resin containing a polar group as the polyolefin resin used for forming the surface layer is a preferred embodiment.
  • This correspondence is preferable because the adhesion between the anisotropic light diffusion film and other materials can be improved.
  • the adhesiveness with a plastic sheet is improved, which is preferable.
  • thermal adhesiveness with acrylic resins and polycarbonate resins widely used as optical materials can be imparted.
  • the polyolefin resin containing a polar group preferably contains at least one monomer of ethylene, propylene, butene, hexene, octene, methylpentene, and cyclic olefin as a skeleton. It may be a homopolymer using one kind of the above monomers or a copolymer using two or more kinds of monomers.
  • the polyolefin resin containing the polar group in the present invention preferably contains at least one kind of polar group.
  • polar groups include carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, hydroxyl groups, glycidyl groups, isocyanate groups, amino groups, imide groups, oxazoline groups, ester groups, ether groups, carboxylic acid metal bases, sulfonic acid metal bases, Examples thereof include phosphonic acid metal bases, tertiary amine bases, and quaternary amine bases.
  • the polar group may be one kind or two or more kinds. It is a preferred embodiment that it contains at least a carboxyl group, which may be appropriately selected depending on the composition of the polyolefin-based resin constituting the light diffusion layer, the type of member to be adhered, the necessary adhesion, and the like.
  • the polyolefin resin containing a polar group in the present invention even if the polar group is directly introduced into the polymer chain of the polyolefin resin, it is in a state of being introduced, added and mixed in another resin. It doesn't matter.
  • the polyolefin resin of the present invention can be used after being modified by reacting a carboxylic acid group, a hydroxyl group, or the like with a compound capable of reacting with the carboxylic acid group or hydroxyl group introduced at the end or inside of the molecular chain.
  • the above polar group-containing polyolefin resin may be used alone or in combination of two or more.
  • blended polyolefin resin and other types of resin which do not contain a polar group may be sufficient.
  • the polyolefin resin containing the polar group is preferably contained at 10% by mass or more. More preferably, it is 30 mass% or more.
  • the polyolefin resin containing the polar group is preferably a crystalline resin. It is preferable to use one having a melting point of 100 to 180 ° C.
  • the polyolefin resin containing the above polar group is not limited as long as it has the above-mentioned characteristics.
  • a resin commercially available as an adhesive polyolefin-based resin can be suitably used.
  • Admer resin TM, manufactured by Mitsui Chemicals
  • Modic resin TM, manufactured by Mitsubishi Chemical
  • Adtex resin TM, Nippon Polyethylene
  • Bond Fast resin TM, manufactured by Sumitomo Chemical
  • the anisotropic light diffusion film of the present invention may be used singly or two or more may be used in an overlapping manner. When two or more sheets are used in an overlapping manner, they may be simply used in an overlapping manner, or may be used by being bonded with an adhesive or a pressure-sensitive adhesive.
  • each film satisfies the above-described characteristics of the present invention by superimposing by using a light diffusion film that does not satisfy the above-described characteristics of the present invention. It is.
  • anisotropic light diffusing film of the present invention and other optical films such as a light diffusing film or a lens film having other characteristics may be used in an overlapping manner. In the case of this method of use, they may be used simply by being overlapped or may be used by being bonded with an adhesive or a pressure-sensitive adhesive.
  • the method for producing the anisotropic light diffusing film of the present invention is not particularly limited as long as the above optical characteristics are satisfied, but a method of forming a film by melt extrusion molding is preferred from the viewpoint of economy.
  • a method of forming a film by melt extrusion molding is preferred from the viewpoint of economy.
  • clogging of the filtration filter of the molten resin in the film forming process is reduced even when the melt extrusion method is used. It has the characteristics that it is excellent in productivity and the clarity of the film obtained is high.
  • the film forming method by the melt extrusion method is not particularly limited, and may be, for example, either a T-die method or an inflation method. Moreover, the film may be an unstretched film or may be subjected to a stretching process.
  • a resin melted by an extruder is extruded from a die into a sheet shape, and the sheet is brought into close contact with a cooling roll to be cooled and solidified to form a film.
  • a liquid pool zone (sometimes referred to as a bank) is not formed at the entrance of the contact portion when the contact is made with the cooling roll. Since the formation of the liquid pool zone occurs when it is pressed against the cooling roll, that is, when it is pressed with a strong pressure, it is preferable to reduce the contact pressure during the contact. For example, it is better to avoid the method of being brought into close contact by pressing with a generally used pressure roll.
  • melted with the extruder is extruded to a sheet form from die
  • the pressing method by a gas pressure and / or a suction method and / or an electrostatic contact method are used. It is preferable that the film is formed by close contact and cooling and solidification.
  • an anisotropic light diffusion film having a high diffusivity ratio which is one of the above-described preferable optical characteristics, in particular, can be stably obtained.
  • the diffusivity ratio may vary greatly depending on the manufacturing equipment used, and stable production may not be possible.
  • it has been found that production by the above production method is preferable. The reason is not clear, but is presumed as follows.
  • the diffusivity ratio is greatly influenced by the influence of the phase structure formed by two types of incompatible resins in the light diffusion layer.
  • the island shape is subject to anisotropy.
  • the diffusivity ratio increases in proportion to the anisotropy of the island shape. That is, in order to increase the diffusion ratio, it is preferable to increase the anisotropy of the island shape.
  • the shape of the island component in the sheet extruded by the melt extrusion method is thin in a shape oriented in the extrusion direction by receiving shear in the die. Further, after being extruded from the die, the sheet is drafted in the molten state, and the island shape becomes thinner in the extrusion direction.
  • the pressing method using the gas pressure and / or the method of adhering and cooling and solidifying by the suction method and / or the electrostatic adhesion method there is no limitation on the pressing method using the gas pressure and / or the method of adhering and cooling and solidifying by the suction method and / or the electrostatic adhesion method.
  • a pressing method using a gas pressure for example, a method such as a so-called air knife method in which pressing is performed with a gas pressure such as air, a vacuum chamber method in which a vacuum nozzle sucks and closely contacts, an electrostatic contact method in which electrostatic force closes, etc.
  • the method may be used alone or a plurality of methods may be used in combination. The latter is a preferred embodiment in that it can increase the thickness accuracy of the film obtained.
  • the anisotropic light diffusion film of the present invention may be produced by either a non-stretching method or a stretching method.
  • a non-stretching method when a polyester resin is used for the light diffusion layer, it is preferable to perform uniaxial stretching.
  • the draw ratio is preferably 2 times or more.
  • the upper limit is not limited, but is preferably less than 10 times.
  • the anisotropic light-diffusion film of this invention may be a single layer, and may be a multilayer structure of two or more layers.
  • the other layer may be a simple transparent layer having no light diffusibility.
  • the structure of the light-diffusion layer may be sufficient as all the layers.
  • it may be produced by a multilayer coextrusion method, or may be carried out by an extrusion lamination method or a dry lamination method.
  • the mixture of the at least two incompatible thermoplastic resins may be blended with each of the thermoplastic resins by an extruder in the film forming process, or in a form that has been previously mixed by a kneading method or the like. It may be used.
  • the parallel light transmittance, haze, and diffusivity are characteristic values that show a proportional behavior macroscopically, but cannot be said to be proportionally microscopically.
  • the thickness of the anisotropic light diffusion film of the present invention is not limited. Generally, 10 to 1000 ⁇ m is preferable, and 30 to 500 ⁇ m is more preferable. When these factors are limited, the preferable thickness range is often a very narrow range, and it is difficult to satisfy all of the optical characteristics at the same time in the thickness range proposed in the prior art. . Generally speaking, the thicker the film thickness, the lower the total light transmittance, the lower the haze, the lower the parallel light transmittance, and the higher the diffusivity. I can do it. When the thickness is adjusted, if the sea-island structure changes greatly due to changes in draft ratio, extrusion flow rate, lip width, etc., the above tendency may be reversed or extremely increased.
  • Another invention of the present invention is a light anisotropic film formed by laminating an anisotropic light diffusing film obtained by the above method and a plastic sheet having a thickness of 0.1 to 5 mm and a total light transmittance of 70 to 100%. It is a diffusible film lamination sheet.
  • the anisotropic light diffusing film obtained by the above-mentioned method has excellent optical properties as described above and can be produced economically. In some applications, the properties other than the optical properties, for example, heat resistance In some cases, mechanical properties such as heat-resistant dimensional stability and rigidity, or properties such as flame retardancy cannot be satisfied.
  • the type of resin and the layer structure are not limited.
  • the thickness of the transparent plastic sheet used in the present invention is more preferably 0.5 to 3 mm. If it is less than 0.1 mm, the reinforcing effect or the complementary effect is insufficient. Moreover, when 5 mm or more, it may become economically disadvantageous or flexibility may be impaired.
  • the total light transmittance of the transparent plastic sheet used in the present invention is more preferably 80 to 100%. More preferably, it is 85 to 100%. If it is less than 70%, the above-mentioned characteristics of the anisotropic light diffusion film cannot be utilized effectively. A non-diffusible material having a high total light transmittance as much as possible is preferable. Also preferred is a method of producing a lamination effect by using a diffusible plastic sheet.
  • resins used for the plastic sheet it is preferable to use resins used for optical applications such as polyester resins, acrylic resins, styrene resins, cyclic polyolefin resins, and polycarbonate resins, but are particularly limited. is not.
  • the manufacturing method of the said anisotropic light-diffusion film lamination sheet is not specifically limited. Specifically, a method of bonding an anisotropic light diffusion film and a plastic sheet can be mentioned.
  • specific examples of the pressure-sensitive adhesive include a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a vinyl-based pressure-sensitive adhesive. Since the anisotropic light diffusion film laminated sheet of the present invention may be used at a high temperature, a pressure-sensitive adhesive that is stable even at room temperature to 120 ° C. is preferable. Among them, acrylic pressure-sensitive adhesives are widely used because they are inexpensive. Whichever adhesive is used, the thickness is preferably 0.5 to 50 ⁇ m.
  • Adhesives include adhesives that are bonded with the help of heat or a catalyst. Specifically, a silicon-based adhesive, a polyurethane-based adhesive, a polyester-based adhesive, an epoxy-based adhesive, a cyanoacrylate-based adhesive, an acrylic-based adhesive, or the like can be used. Since the anisotropic light diffusion film laminated sheet of the present invention may be used at a high temperature, an adhesive that is stable even at room temperature to 120 ° C. is preferable. Among these, epoxy adhesives are excellent in strength and heat resistance, and can be suitably used. Since the cyanoacrylate adhesive is excellent in immediate effect and strength, it can be used for efficient laminate sheet production.
  • Polyester adhesives are particularly suitable for producing laminated sheets because they are excellent in strength and processability. These adhesives are roughly classified into a thermosetting type, a hot melt type, and a two-component mixed type depending on the bonding method, and a thermosetting type or a hot melt type capable of continuous production is preferably used. Whichever adhesive is used, the thickness is preferably 0.5 to 50 ⁇ m.
  • the method of laminating the plastic sheet and the anisotropic light diffusing film with an adhesive or a pressure-sensitive adhesive is performed by laminating a roll-to-roll or roll-to-sheet process to obtain a roll-shaped or single-wafer-shaped product.
  • the adhesive is coated on either a plastic sheet or an anisotropic light diffusing film, dried and then laminated by lamination with a counterpart material and a roller.
  • the gravure coater method coating is performed by rotating a gravure roll that is partially immersed in an adhesive and bringing the film fed by a backup roll into contact with the gravure roll to which the adhesive is attached.
  • the coating amount can be adjusted by controlling the number of rotations of the roll and the viscosity of the adhesive.
  • the reverse coater method is also a method similar to the gravure coater method, but the amount of adhesive adhering to the coating roll is adjusted by a metering roll installed in contact therewith.
  • a double-sided adhesive sheet may be used.
  • an optically highly transparent pressure-sensitive adhesive but it is not particularly limited.
  • an adhesive sheet having light diffusibility may be used.
  • light diffusibility may be imparted to the pressure-sensitive adhesive layer.
  • an anchor coating treatment or an easy adhesion treatment transparent plastic sheet is used.
  • Incorporating means such as use is one of the preferred embodiments.
  • the anisotropic light diffusion film or the anisotropic light diffusion film laminated sheet of the present invention has the excellent optical properties as described above, it is preferably used as a light diffusion film of an illumination device using an LED light source.
  • the present invention is not limited, and for example, it is also effective when used for an illumination device using a light source other than an LED light source such as a fluorescent lamp.
  • a light source other than an LED light source such as a fluorescent lamp.
  • a lighting device for a fluorescent lamp light source even if the distance between the fluorescent lamp and the light diffusing film or the light diffusing film laminated sheet is reduced, a high degree of light diffusibility is exhibited. The effect of reducing the number of fluorescent lamps is exhibited.
  • anisotropic light diffusion film and anisotropic light diffusion film laminated sheet of the present invention are greatly improved in diffusibility compared with conventionally known light diffusion films, so it can be used to improve the brightness of LCDs using fluorescent lamps as the light source. In this case, the number of optical function adjusting films such as a light diffusion film can be reduced.
  • Another invention of the present invention is an LED light source in which the anisotropic light diffusing film described above or the anisotropic light diffusing film laminated sheet described above is attached to an outer surface or an inner surface of a light emitting portion of a light irradiation device using an LED light source. It is the lighting device used.
  • the lighting device is a device generally referred to as a light or a lamp, such as a lighting device for brightly illuminating an object and a light emitting device for directly viewing emitted light.
  • the method for attaching the light diffusion film and the laminated sheet thereof is not limited.
  • it may be affixed to the outer surface or inner surface of the outer plate of the light-emitting portion with an adhesive or adhesive, or may be simply overlapped and attached.
  • it may be fixed to the entire surface using an adhesive or an adhesive, or may be fixed by partial use.
  • a light diffusion film or a laminated sheet thereof may be inserted and attached to the inner surface of the outer tube so as to be along the inner side of the outer tube.
  • the outer plate may be eliminated and only the light diffusion film or the laminated sheet of the present invention may be attached.
  • the lighting device in the present invention is not limited in its type and usage as long as it has a function of brightening a specific place for some purpose. For example, the usage method as described later is mentioned.
  • the anisotropic diffusion film of the present invention it is possible to provide an illuminating device that irradiates the spot-like light of the LED light source in a straight line with uniform light.
  • an illuminating device does not want to leak light other than necessary parts such as signboards and information boards of the type that illuminate from the oblique side of the viewing side, display of museums, product display in stores, desk lamps, walkways and sidewalks
  • it can be used as various illuminating devices such as a light emitting part and an edge light part in a backlight unit such as a liquid crystal display and a backlight type notice board, and a light of a copying machine.
  • the anisotropic diffusion film of the present invention can be effectively used in an illuminating device in which LED light sources are arranged in a long line in one direction.
  • the arrangement of the LEDs is not limited to a single row but may be a plurality of rows as long as they are arranged in an elongated state as a whole.
  • a characteristic illumination device can be obtained also when the main diffusion direction of the film is orthogonal to the LED rows. In this case, even if the LED light sources are arranged in a long line in one direction, the light can be widely diffused and illuminated in the direction orthogonal to the line. It can be used as an illumination device similar to a straight tube fluorescent lamp in a room, and the room can be illuminated uniformly.
  • the anisotropic light diffusing film or the anisotropic light diffusing film laminated sheet of the present invention has the excellent optical characteristics as described above, it can be suitably used as a member for improving the luminance and illuminance of the backlight device. It is important that the anisotropic light diffusing film or the light diffusing film laminated sheet of the present invention is installed on the light exit surface of the backlight unit.
  • the installation method of the anisotropic light diffusion film or the anisotropic light diffusion film laminated sheet is not limited. They may be simply placed one on top of the other, or may be fixed with an adhesive or adhesive. Moreover, you may fix with a double-sided adhesive tape. Moreover, you may install in the lowest surface of the liquid crystal panel installed in the upper surface of a backlight apparatus. By the correspondence, the above-described effects of the present invention can be efficiently expressed.
  • the backlight unit in which the anisotropic light diffusing film or the anisotropic light diffusing film laminated sheet of the present invention is used is not limited in any way as long as it is a unit having an outgoing light surface on at least one side.
  • the edge light method or the direct method may be used.
  • the structure of the light guide plate in the case of the edge light system is not limited.
  • the light source used for the backlight unit is not limited.
  • any of a light bulb, a light emitting diode (LED), an electroluminescence panel (EL), a cold cathode tube (CCFL) and a hot cathode tube (HCFL) may be used, or a combination of these or other light sources may be used.
  • the anisotropic light diffusing film or the anisotropic light diffusing film laminated sheet of the present invention is a backlight having high brightness, reduced angle dependency of brightness, in-plane brightness homogeneity and pattern concealing property even when only one of these members is used. Since it is possible to impart the optical properties that the apparatus needs to have, it is important to use one sheet, but two or more sheets may be used together, and conventionally known lens films, light diffusion films, etc. You may use together. Further, other light diffusion sheets and light diffusion plates may be used in combination. In this case, a plurality of types of optical members may be used in combination. It is preferable to select and use it appropriately according to market demand characteristics and economic efficiency.
  • the backlight device of the present invention is not limited to use as a display device. You may use as a light source for the said illuminating device.
  • GP-200 manufactured by Murakami Color Research Co., Ltd.
  • the width (half width) of the angle at the half height of the peak height of the obtained variable angle luminous intensity curve of the transmitted light was obtained.
  • the above measurement was carried out with the winding direction of the anisotropic light diffusion film fixed in the vertical direction and the horizontal direction, and the diffusivity ratio 1 (DH1 / DL1) was determined with DH1 as the larger half width and DL1 as the smaller half width.
  • the diffusivity ratio 2 (DH2 / DL2) was obtained by setting DH2 as the greater frequency of the angle between the peak rising angle and the peak ending angle and DL2 as the smaller frequency (see FIG. 1).
  • the portion was observed with a magnifying glass 10 times, and the most advanced angle where the line of the peak disappeared was defined as each angle. A clear determination can be made if this is done.
  • the measurement when there was a difference in the surface roughness of the light diffusing film, the measurement was performed by fixing the light diffusing film in the direction in which light passes when actually used. The surface on which the light receiver is moved is defined as the equator plane.
  • Measurement was performed using an automatic variable angle photometer (GP-200: manufactured by Murakami Color Research Co., Ltd.). Transmission measurement mode, light incident angle: 0 ° (angles perpendicular to the sample surface, both right and left, right and left), light receiving angle: -90 ° to 90 ° (angle on the equator plane), filter: ND10 used, beam stop 10.5 mm (VS-1 3.0), light-receiving aperture: 9.1 mm (VS-3 4.0), and measurement with a variable angle interval of 0.1 degree. The measurement was performed by changing the settings of SENSITIVITY and HIGH VOLTON so that the ratio was 40 to 90%.
  • the height (H0) at an angle of 0 degree of the variable angle luminous intensity curve of the obtained transmitted light is obtained. Except changing the light incident angle to 60 ° (angle on the equator plane), the height (H60) at an angle 0 degree of the variable light intensity curve of the transmitted light when measured under the same conditions as described above is obtained. Inflection degree was calculated
  • required by this method. (See Figure 2.) Inflection of light H60 / H0 ⁇ 100 (%) (1) The surface on which the light receiver is moved is defined as the equator plane. The inflection degree of the light is obtained by measuring in the main diffusion direction. In the above measurement, when there was a difference in the surface roughness of the light diffusing film, the measurement was performed by fixing in the direction in which light passes in the same direction as when actually used.
  • ⁇ Average surface roughness ratio> Using a universal surface shape measuring device MODEL SE-3C manufactured by Kosaka Laboratory Ltd., longitudinal magnification: 2000 to 10000, cutoff: 0.25 mm, measurement length: 8 mm, measurement speed: 0.5 mm / min. . The above measurement is performed by measuring the average surface roughness in the winding direction of the light diffusion film and the direction perpendicular to the direction, and the surface roughness ratio (RaV / RaV) which is the ratio of RaV and RaH, which are the respective average surface roughnesses. RaH). Each measurement was performed 5 times, and the average value was used.
  • thermoplastic resin Based on JIS K 7210 A method, it measured on condition of 230 degreeC and 2.16kgf. Some resins were measured under the conditions described in the examples.
  • the refractive index of the resin was determined according to the Becke line method (JIS K7142B method) ISO 489, and the value of the sodium d line was obtained with an Abbe refractometer.
  • Cyclic polyolefin resin which is a norbornene-ethylene copolymer (TOPAS (TM) 6013 S-04 Topas Advanced Polymers melt flow rate: 2.0 (230 ° C.) refractive index: 1.53) 35 parts by mass, ethylene Block copolymer resin made of octene (INFUSE (TM) D9817.15 manufactured by Dow Chemical Co., Ltd.) Melt flow rate: 26 (230 ° C.) Refractive index: 1.49) 65 parts by mass using a PCM45 extruder manufactured by Ikekai Tekko Co., Ltd.
  • TOPAS (TM) 6013 S-04 Topas Advanced Polymers melt flow rate: 2.0 (230 ° C.) refractive index: 1.53) 35 parts by mass, ethylene Block copolymer resin made of octene (INFUSE (TM) D9817.15 manufactured by Dow Chemical Co., Ltd.) Melt flow rate: 26 (230 ° C.) Refractive index: 1.49) 65 parts by mass using
  • An anisotropic light diffusing film having a thickness of 400 ⁇ m was obtained by melting and mixing at a resin temperature of 250 ° C., extruding with a T-die, and cooling with a mirror cooling roll. The film was adhered to the cooling roll at the time of cooling using a vacuum chamber.
  • the characteristics of the obtained anisotropic light diffusion film are shown in Table 1.
  • the anisotropic light diffusion film obtained in this example was excellent in anisotropy of light diffusion. Moreover, the brightness was bright and the spot disappearance property was excellent, and the anisotropic light diffusion film was used and it was high quality. Moreover, the color difference by a light resistance test was 1.0, and it was excellent also in light resistance.
  • Example 2 In the method of Example 1, the resin was blended with 50 parts by mass of a cyclic polyolefin resin (TOPAS (TM) 6015S-04 Topas Advanced Polymers, melt flow rate: 0.41 (230 ° C.), refractive index: 1.53).
  • Block copolymer resin composed of ethylene and octene INFUSE (TM) D91011.15 manufactured by Dow Chemical Co., Ltd.) Melt flow rate: 2.1 (230 ° C.) Refractive index: 1.49)
  • An anisotropic light diffusing film was obtained in the same manner as in Example 1 except that the thickness was changed to 200 ⁇ m. The characteristics of the obtained anisotropic light diffusion film are shown in Table 1.
  • the anisotropic light diffusing film obtained in this example is slightly inferior in spot disappearance than the anisotropic light diffusing film obtained in Example 1, but is further light diffusing than the anisotropic light diffusing film obtained in Example 1.
  • the anisotropy and brightness were excellent, and the anisotropic light diffusion film was high quality.
  • the color difference by a light resistance test was 1.0, and it was excellent also in light resistance.
  • Example 3 A light diffusion film was obtained in the same manner as in Example 2 except that the film thickness was changed to 150 ⁇ m by the method of Example 2.
  • Table 1 shows the characteristics of the obtained light diffusion film.
  • the light diffusing film obtained in this example was slightly inferior in brightness to the light diffusing film obtained in Example 1, but was superior in brightness and was high quality as a light diffusing film.
  • the color difference by a light resistance test was 1.0, and it was excellent also in light resistance.
  • Example 4 In the method of Example 1, the resin composition was changed to 50 parts by mass of cyclic polyolefin resin (TOPAS (TM) 5013 S-04 Topas Advanced Polymers, melt flow rate: 8.7 (230 ° C.)), a block composed of ethylene and octene A copolymer resin (INFUSE (TM) D9817.15 melt flow rate: 26 (230 ° C.), manufactured by Dow Chemical Co., Ltd.) is 50 parts by mass, and the film thickness is changed to 200 ⁇ m. An isotropic light diffusion film was obtained. The characteristics of the obtained anisotropic light diffusion film are shown in Table 1.
  • the anisotropic light diffusing film obtained in this example had the same characteristics as the anisotropic light diffusing film obtained in Example 2, and was high quality as an anisotropic light diffusing film. Moreover, the color difference by a light resistance test was 1.0, and it was excellent also in light resistance.
  • Example 5 In the method of Example 1, the resin composition was changed to 50 parts by mass of cyclic polyolefin-based resin (TOPAS (TM) 6015 S-04 Topas Advanced Polymers, melt flow rate: 0.41 (230 ° C.)), random consisting of ethylene and octene. Copolymer resin (ENGAGE (TM) 8137 manufactured by Dow Chemical Co., Ltd.) Melt flow rate: 30 (190 ° C.) Refractive index: 1.52) Same as Example 1 except that the film thickness is changed to 50 ⁇ m and the film thickness is 200 ⁇ m. An anisotropic light diffusion film was obtained by this method. The characteristics of the obtained anisotropic light diffusion film are shown in Table 1.
  • the anisotropic light diffusing film obtained in this example had the same characteristics as the anisotropic light diffusing film obtained in Example 2, and was high quality as an anisotropic light diffusing film. Moreover, the color difference by a light resistance test was 1.0, and it was excellent also in light resistance.
  • a mixture of 15 parts by mass of low density polyethylene resin (SP1540) manufactured by Co., Ltd. was supplied to a single-screw extruder, melted at 280 ° C., passed through a filter and a gear pump, removed foreign matter, and leveled the amount of extrusion. Thereafter, the sheet was discharged from a T-die onto a cooling drum whose temperature was controlled at 25 ° C.
  • a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.
  • the film was stretched 5.0 times in the longitudinal direction at a temperature of 103 ° C. in the longitudinal direction to obtain an anisotropic light diffusion film having a thickness of 150 ⁇ m.
  • the characteristics of the obtained anisotropic light diffusion film are shown in Table 1.
  • the anisotropic light diffusion film obtained in this example was of high quality. However, the color difference change by the light resistance test was 3.7, which was slightly inferior to the anisotropic light diffusion films obtained in Examples 1 to 5.
  • Example 7 In the method of Example 6, except that the low density polyethylene resin is changed to a modified polypropylene resin (CAP350 manufactured by Dainichi Seika Co., Ltd.) and the film thickness is 200 ⁇ m, the same method as in Example 6, An anisotropic light diffusion film was obtained. The characteristics of the obtained anisotropic light diffusion film are shown in Table 1. The anisotropic light diffusion film obtained in this example had the same quality as the anisotropic diffusion film obtained in Example 6.
  • CAP350 manufactured by Dainichi Seika Co., Ltd.
  • Example 8 50 parts by mass of fluorine-based resin (Kynar 720 (PVDF) manufactured by Arkema Corporation, melt flow rate: 10 (230 ° C., 5 kgf)) and polymethylpentene resin (TPX (TM) DX820, manufactured by Mitsui Chemicals, melt flow rate: 110 ( 260 ° C., 5 kgf) Refractive index: 1.46 (reference value)) 50 parts by mass are melt-mixed at a resin temperature of 250 ° C. using a PCM45 extruder manufactured by Ikekai Tekko Co., Ltd. Was cooled to obtain an anisotropic light diffusion film having a thickness of 225 ⁇ m. The film was adhered to the cooling roll during the cooling using an air knife.
  • the anisotropic light diffusion film obtained in this example was high quality as an anisotropic light diffusion film. Further, the color difference by the light resistance test was 0.9, which was excellent in light resistance.
  • Example 9 Fluorine resin (Kynar 720 (PVDF) manufactured by Arkema, Ltd. Melt flow rate: 10 (230 ° C., 5 kgf)) and 50 parts by mass of cyclic polyolefin resin (TOPAS (TM) 6013 S-04 Advanced Advanced Polymers) Melt flow rate: 2.1 (230 ° C., 2.16 kgf)) 50 parts by mass are melt-mixed at a resin temperature of 0 ° C. using a PCM45 extruder manufactured by Ikekai Tekko Co., Ltd., extruded with a T die, and cooled with a mirror-surface cooling roll. An anisotropic light diffusion film having a thickness of 70 ⁇ m was obtained.
  • the film was adhered to the cooling roll at the time of cooling using a vacuum chamber. Moreover, the corona treatment was given to one side.
  • the characteristics of the obtained anisotropic light diffusion film are shown in Table 1.
  • the anisotropic light diffusion film obtained in this example was high quality as an anisotropic light diffusion film. Moreover, the color difference by a light resistance test was 1.0, and it was excellent also in light resistance.
  • Example 1 a light diffusing film is obtained in the same manner as in Example 1 except that it is changed to a satin-finished cooling roll and is changed to be cooled by pressure-bonding to the cooling roll using a mirror surface pressing roll. It was. Table 1 shows the characteristics of the obtained light diffusion film.
  • the light diffusion film obtained in this comparative example was inferior in light diffusion anisotropy, and was of low quality as an anisotropic light diffusion film.
  • Block copolymer resin (INFUSE made by Dow Chemical Co., Ltd.) consisting of 35 parts by mass of cyclic polyolefin resin (TOPAS (TM) 6015 S-04 Topas Advanced Polymers melt flow rate: 0.41 (230 ° C.)), ethylene and octene (TM) D9807.15 Melt flow rate: 29 (230 ° C)) 65 parts by mass was melt-mixed at a resin temperature of 250 ° C using a PCM45 extruder manufactured by Ikekai Tekko Co., Ltd. Was cooled to obtain a light diffusion film having a thickness of 300 ⁇ m. The film was adhered to the cooling roll at the time of cooling using a vacuum chamber. Table 1 shows the characteristics of the obtained light diffusion film.
  • the light diffusion film obtained in this comparative example was inferior in light diffusion anisotropy, and was of low quality as an anisotropic light diffusion film.
  • the light diffusion film obtained in this comparative example was inferior in spot disappearance and diffusivity, and was low quality as an anisotropic light diffusion film.
  • the film was stretched 3.0 times in the longitudinal direction at a temperature of 103 ° C. in the longitudinal direction to obtain a light diffusion film having a thickness of 75 ⁇ m.
  • Table 1 shows the characteristics of the obtained light diffusion film.
  • the light diffusing film obtained in this comparative example was inferior in spot disappearance and diffusivity like the light diffusing film obtained in comparative example 2, and was low quality as an anisotropic light diffusing film.
  • Comparative Example 7 The properties of the light diffusion film made of polycarbonate resin embossed on the surface were evaluated. The results are shown in Table 1.
  • the light diffusing film obtained in this comparative example has low light diffusibility anisotropy, high parallel light transmittance, poor spot extinction and brightness spread, and is low as an anisotropic light diffusive film. It was quality. In addition, the color difference change was as high as 9.5 and the light resistance was poor.
  • Example 8 In the method of Example 6, a light diffusion film was obtained in the same manner as in Example 6 except that the draw ratio was 1.5 times and the thickness of the obtained film was 25 ⁇ m. Table 1 shows the characteristics of the obtained light diffusion film.
  • the light diffusing film obtained in this comparative example was excellent in terms of brightness, but was inferior in spot disappearance due to high parallel light transmittance and low haze. Moreover, anisotropy was also inferior and it was low quality as an anisotropic light-diffusion film.
  • Example 9 In the method of Example 6, a light diffusion film was obtained in the same manner as in Example 6 except that the thickness of the obtained film was 200 ⁇ m. Table 1 shows the characteristics of the obtained light diffusion film.
  • the light diffusing film obtained in this Comparative Example was excellent in anisotropy and spot disappearance but inferior in brightness, and was of low quality as an anisotropic light diffusing film.
  • Example 10 In the method of Example 7, a light diffusion film was obtained in the same manner as in Example 6 except that the draw ratio was 1.5 times and the thickness of the obtained film was 25 ⁇ m. Table 1 shows the characteristics of the obtained light diffusion film.
  • the light diffusing film obtained in this comparative example was excellent in terms of brightness, but was inferior in spot disappearance due to high parallel light transmittance and low haze. Moreover, anisotropy was also inferior and it was low quality as an anisotropic light-diffusion film.
  • Example 11 In the method of Example 7, a light diffusion film was obtained in the same manner as in Example 6 except that the thickness of the obtained film was changed to 300 ⁇ m. Table 1 shows the characteristics of the obtained light diffusion film.
  • the light diffusing film obtained in this Comparative Example was excellent in anisotropy and spot disappearance but inferior in brightness, and was of low quality as an anisotropic light diffusing film.
  • Example 12 In the method of Example 8, a light diffusion film was obtained in the same manner as in Example 6 except that the thickness of the obtained film was 350 ⁇ m. Table 1 shows the characteristics of the obtained light diffusion film.
  • the light diffusing film obtained in this Comparative Example was excellent in anisotropy and spot disappearance but inferior in brightness, and was of low quality as an anisotropic light diffusing film.
  • Example 13 In the method of Example 9, a light diffusion film was obtained in the same manner as in Example 6 except that the thickness of the obtained film was 125 ⁇ m. Table 1 shows the characteristics of the obtained light diffusion film.
  • the light diffusing film obtained in this Comparative Example was excellent in anisotropy and spot disappearance but inferior in brightness, and was of low quality as an anisotropic light diffusing film.
  • Example 10 The anisotropic light diffusing film obtained in Examples 1 to 9 was bonded to a highly transparent polyester film (Cosmo Shine A4300 manufactured by Toyobo Co., Ltd.) having a thickness of 250 ⁇ m and a total light transmittance of 92%, using an optical double-sided adhesive sheet. Thus, an anisotropic light diffusion film laminated sheet was obtained. All the laminated sheets had the same optical characteristics as the respective anisotropic light diffusion films, and were high quality as a light diffusion material for an illumination device using an LED light source. Further, the obtained anisotropic light diffusing film laminated sheet had improved non-optical properties such as heat resistance and strength as compared with the anisotropic light diffusing films obtained in Examples 1 to 9.
  • Example 11 The anisotropic light diffusing film obtained by the methods of Examples 1 to 9 was switched to a roll method in the methods of Examples 1 to 9 while suppressing adhesion of the film to the cooling roll at the time of cooling, and a polyurethane system on the holding roll side.
  • An anisotropic light diffusing film laminated sheet in which a polycarbonate sheet is laminated is obtained by passing a polycarbonate sheet having a thickness of 200 ⁇ m and a total light transmittance of 88% that is surface-treated with an anchor coating agent using an adhesive of It was. At this time, the extrusion amount and the pressing pressure were adjusted so that a liquid pool zone could not be formed.
  • the anisotropic light diffusing film laminated sheet obtained in this example has optical properties equivalent to those of the anisotropic light diffusing film obtained in Examples 1 to 9, and light diffusion for an illumination device using an LED light source. It was high quality as a material. Further, non-optical properties such as heat resistance and strength were improved as compared with the light diffusion films obtained in Examples 1 to 9.
  • Example 12 Using a 40W daylight white clear cover fluorescent lamp type LED illuminator (MLT-40KC) manufactured by Momo Alliance, the anisotropic light diffusion film obtained in Examples 1 to 9 was applied to the clear cover surface in the main diffusion direction. was affixed with an optical double-sided tape so as to be in a direction perpendicular to the longitudinal direction of the fluorescent lamp type LED illumination lamp. The light from the point-like LED light source became thin linear light.
  • MLT-40KC 40W daylight white clear cover fluorescent lamp type LED illuminator
  • Example 13 the anisotropic light diffusing film was affixed with a double-sided optical tape in a direction in which the main diffusion direction is parallel to the longitudinal direction of the fluorescent lamp type LED illumination lamp.
  • the light from the pointed LED light source appeared to shine in a thin round shape in a direction perpendicular to the longitudinal direction of the fluorescent lamp.
  • Example 14 Using two melt extruders, in the first extruder, cyclic polyolefin resin (TOPAS (TM) 6013S-04 Topas Advanced Polymers melt flow rate: 2.0 (230 ° C., 2.16 kgf))
  • a block copolymer resin comprising 35 parts by mass, ethylene and octene (INFUSE (TM) D9817.15 manufactured by Dow Chemical Co., Ltd., melt flow rate: 26 (230 ° C., 2.16 kgf)) 65 parts by mass is used as a light diffusion layer.
  • IPFUSE (TM) D9817.15 manufactured by Dow Chemical Co., Ltd.
  • melt flow rate 26 (230 ° C., 2.16 kgf)
  • the polypropylene-based adhesive resin (Admer (TM) QF551, made by Mitsui Chemicals, Ltd., melt flow rate: 5.7 (190 ° C., 2.16 kgf)) becomes both surface layers (thermal adhesion layers). Furthermore, after melt coextrusion by the T-die method, the total thickness of 40 is obtained by cooling with a mirror-like cooling roll. Both surfaces of ⁇ m was obtained anisotropic light-diffusing film laminated with heat adhesion layer. The thickness of the heat bonding layer was 40 ⁇ m on both sides. The film was closely attached to the cooling roll during the cooling in the same manner as in Example 1. Even when the film was continuously formed for a long time, no generation of eyes was observed.
  • Admer (TM) QF551 made by Mitsui Chemicals, Ltd., melt flow rate: 5.7 (190 ° C., 2.16 kgf)
  • the total thickness of 40 is obtained by cooling with a mirror-like cooling roll. Both surfaces of ⁇ m was obtained anisotropic light
  • Table 1 shows the characteristics of the anisotropic light diffusion film obtained in this example.
  • the obtained anisotropic light diffusing film has the same optical characteristics as in Example 1 and is excellent in thermal adhesiveness, and the dimensional stability of the anisotropic light diffusing film is improved by thermally bonding to the base material. .
  • the thermal adhesion and dimensional stability were evaluated by the following methods. Both were ⁇ .
  • the method of Example 1 was carried out, when the film was continuously formed for a long time, the eyes and the eyes may be generated.
  • ⁇ Thermal adhesiveness> Set a 3mm thick and smooth acrylic board (Mitsubishi Rayon Co., Ltd .: Acrylite) on the fixed table of the heat press machine, place the sample on the acrylic board, and then A silicone rubber sheet having a thickness of 3 mm (hardness HsA 50 °) is laid on the surface, and is pressed from above the silicone rubber sheet with a pressure indenter whose surface temperature is set to 180 ° C., at a pressure of 49 N / cm 2 . Pressing pressure was applied for 30 seconds.
  • a 3mm thick and smooth acrylic board Mitsubishi Rayon Co., Ltd .: Acrylite
  • Adhesive strength is 0.1 N / 15 mm or more: ⁇ Adhesive strength is less than 0.1 N / 15 mm: ⁇
  • ⁇ Dimensional stability> a sample obtained by thermally bonding an anisotropic light diffusing film to an acrylic plate is allowed to stand in an oven adjusted to 80 ° C. for 240 hours and heated, and then the longitudinal and lateral directions of the anisotropic light diffusing film are measured. The dimensions were measured, compared with the respective dimensions before the heating treatment, and judged according to the following criteria. When dimensional change due to heating treatment is less than 0.1% in either direction: ⁇ When the dimensional change due to the heating treatment is 0.1% or more in at least either: ⁇
  • Example 15 In the method of Example 14, the resin extruded by the second extruder was changed to a polypropylene-based adhesive resin (Admer (TM) QF551, Mitsui Chemicals, melt flow rate: 5.7 (190 ° C.)), An anisotropic light diffusion film was obtained in the same manner as in Example 14 except that polypropylene resin FS2011DG3 (manufactured by Sumitomo Chemical Co., Ltd., Sumitomo Nobrene (TM)) was used. Table 1 shows the characteristics of the anisotropic light diffusion film obtained in this example. The obtained anisotropic light diffusing film was excellent in light diffusing properties, and even when it was continuously formed for a long time, it was not visually observed. However, the thermal adhesion was inferior to the anisotropic light diffusing film obtained in Example 14.
  • Admer (TM) QF551, Mitsui Chemicals, melt flow rate: 5.7 (190 ° C.) a polypropylene-based adhesive resin
  • Example 16 to 20 Using the anisotropic light diffusing films obtained in Examples 1, 2, 5, 6 and 8, respectively, the front luminance and the angle dependency of luminance and the pattern when used in a backlight device for a liquid crystal display device by the following method Concealment was measured. The results are shown in Table 2.
  • the anisotropic light diffusing film obtained in any of the examples also has excellent optical characteristics as described in each example, and furthermore, since the inflection degree of light is high, the use of one anisotropic light diffusing film can be used.
  • the front luminance is high, the angle dependency of luminance is small, and the pattern concealing property is excellent, and it is high quality as a luminance improving member of a backlight device for a liquid crystal display device.
  • ⁇ Front brightness when used in a backlight device for a liquid crystal display> Near the center on the acrylic plate on the outgoing light side of a 19-inch light guide plate type (mesh type using a white reflective film) with three cold cathode tubes on each side of the long diameter side (lateral direction)
  • a 40 mm ⁇ 60 mm square (60 mm side is the lateral direction) evaluation sample was set on the part (simply placed on top of each other, or if the sample was curled, etc., the four corners were fixed with tape).
  • a black shading paper provided with a 30 mm ⁇ 50 mm square cut-out portion (50 mm side is the horizontal direction) was placed so that the center of the cut-out portion was the center of the evaluation sample, and the luminance was measured in a dark room.
  • the black light-shielding paper was fixed so that the entire backlight unit was covered, and measurement was performed so that light did not leak.
  • the backlight unit was installed horizontally and measured.
  • the brightness was measured using a Topcon Spectroradiometer SR-3A manufactured by Topcon Technohouse Co., Ltd. at a measurement angle of 2 degrees, a distance from the backlight unit surface of 40 cm, and the center of the sample for evaluation directly below. It was measured.
  • the sample for evaluation was installed such that the main diffusion direction was perpendicular to the longitudinal direction of the cold cathode tube.
  • Example 21 to 23 About the anisotropic light-diffusion film obtained in Example 1, 5 and 8, the in-plane brightness
  • the anisotropic light diffusing film obtained in either example had high average brightness, high in-plane brightness uniformity, and high quality as a light diffusing film for a backlight device.
  • the cold cathode tube used was set so that the longitudinal direction of the cold cathode tube was the longitudinal direction (lateral direction) of the backlight unit.
  • the luminance measuring device was measured just above the center of the sample, and the distance between the transparent acrylic plate surface and the luminance meter incident light surface was set at a position of 120 cm.
  • the backlight unit was installed horizontally and measured. In this measurement, the sample for evaluation was installed so that the main diffusion direction was perpendicular to the longitudinal direction of the cold cathode tube.
  • the anisotropic light diffusing film and laminated sheet of the present invention have a so-called anisotropic light diffusing function that is excellent in light transmittance and diffusivity and condenses and diffuses light in a specific direction, so that the LED light source is strong straight ahead Therefore, even when the number of LED light sources is reduced, uniform illumination can be achieved, for example, when linear illumination is required.
  • it when used as a light source for advertising media, illumination, etc., it has a feature that it can enhance decorativeness and electrical decoration.
  • the transmittance of light traveling straight is small, when used for an illuminating device using an LED light source, the light source spot of strong light is made invisible, and the degree of decrease in the transmittance of the light beam is further reduced.
  • the anisotropic light-diffusion film lamination sheet for illuminating devices using the LED light source of this invention can improve non-optical characteristics, such as heat resistance and intensity
  • the anisotropic light diffusion film of the present invention has an anisotropic light diffusion function and has a higher diffusibility than a conventionally known anisotropic light diffusion film, so when used as a diffusion film of a light guide plate type display. It has the feature that the brightness improvement effect is larger than that.
  • the anisotropic light diffusion film of the present invention and a laminated sheet using the same are used as an optical member of a backlight device, even if the film or the laminated sheet is used, high luminance and luminance angle dependency Therefore, the optical characteristics required to be provided as an optical member for a backlight device, such as a reduction in brightness, in-plane luminance uniformity, and pattern concealing property, can be imparted, so that the economic efficiency of the backlight device can be improved.
  • the backlight device of the present invention has a high front luminance close to that of a backlight device using a lens film, and the angle dependency of luminance, which is a problem of the backlight device using a lens film, is reduced. Therefore, for example, when used in a large TV, there is an advantage that a decrease in the brightness of the screen when viewed obliquely is suppressed.
  • this feature for example, it is useful as a backlight device of a display that is often viewed from an oblique direction such as car navigation.
  • the backlight device of the present invention when used with a backlight device for a lamp for indoor or in-house lighting, there is an advantage that uniform illuminance can be obtained over a wide range as compared with a backlight device using a lens film. Furthermore, the backlight device of the present invention has the advantage that it is highly economical because all of the above characteristics can be imparted by using a single member. Therefore, the backlight device of the present invention can be effectively used in a liquid crystal display device, indoor lighting, an interior illumination panel, and the like. Moreover, according to the method for producing an anisotropic light diffusing film of the present invention, the anisotropic light diffusing film of the present invention having the above characteristics can be produced economically and stably. Therefore, the contribution to the industry is great.

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JP2012141593A (ja) * 2010-12-16 2012-07-26 Lintec Corp 光拡散フィルムおよび光拡散フィルムの製造方法
JP2012141592A (ja) * 2010-12-15 2012-07-26 Lintec Corp 異方性光拡散フィルム用組成物および異方性光拡散フィルム
WO2012118082A1 (ja) * 2011-03-01 2012-09-07 東洋紡績株式会社 視野角向上フィルム及び液晶表示装置
JP2012172136A (ja) * 2011-02-24 2012-09-10 Riken Technos Corp 熱可塑性エラストマー組成物
WO2012128088A1 (ja) * 2011-03-23 2012-09-27 コニカミノルタアドバンストレイヤー株式会社 照明装置、棚板照明装置、この棚板照明装置を備えた棚板ユニットおよびショーケース
JP2012220662A (ja) * 2011-04-07 2012-11-12 Toyobo Co Ltd 視野角向上フィルム及び液晶表示装置
JP2012226158A (ja) * 2011-04-20 2012-11-15 Toyobo Co Ltd 視野角向上フィルム、視野角向上フィルム積層体及び液晶表示装置
JP2014199377A (ja) * 2013-03-30 2014-10-23 大日本印刷株式会社 異方性拡散シート、異方性拡散シートの製造方法
WO2015151319A1 (ja) * 2014-03-31 2015-10-08 積水化成品工業株式会社 光拡散体及びその用途
US20220299682A1 (en) * 2019-10-31 2022-09-22 Kimoto Co., Ltd. Light diffusion film

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JP2012141592A (ja) * 2010-12-15 2012-07-26 Lintec Corp 異方性光拡散フィルム用組成物および異方性光拡散フィルム
JP2012141593A (ja) * 2010-12-16 2012-07-26 Lintec Corp 光拡散フィルムおよび光拡散フィルムの製造方法
JP2012172136A (ja) * 2011-02-24 2012-09-10 Riken Technos Corp 熱可塑性エラストマー組成物
CN103403581A (zh) * 2011-03-01 2013-11-20 东洋纺株式会社 视角提高膜及液晶显示装置
WO2012118082A1 (ja) * 2011-03-01 2012-09-07 東洋紡績株式会社 視野角向上フィルム及び液晶表示装置
JPWO2012118082A1 (ja) * 2011-03-01 2014-07-07 東洋紡株式会社 視野角向上フィルム及び液晶表示装置
CN103429954A (zh) * 2011-03-23 2013-12-04 柯尼卡美能达株式会社 照明装置、架板照明装置、具备该架板照明装置的架板单元以及陈列柜
WO2012128088A1 (ja) * 2011-03-23 2012-09-27 コニカミノルタアドバンストレイヤー株式会社 照明装置、棚板照明装置、この棚板照明装置を備えた棚板ユニットおよびショーケース
JP5794295B2 (ja) * 2011-03-23 2015-10-14 コニカミノルタ株式会社 照明装置、棚板ユニット、およびショーケース
JP2012220662A (ja) * 2011-04-07 2012-11-12 Toyobo Co Ltd 視野角向上フィルム及び液晶表示装置
JP2012226158A (ja) * 2011-04-20 2012-11-15 Toyobo Co Ltd 視野角向上フィルム、視野角向上フィルム積層体及び液晶表示装置
JP2014199377A (ja) * 2013-03-30 2014-10-23 大日本印刷株式会社 異方性拡散シート、異方性拡散シートの製造方法
WO2015151319A1 (ja) * 2014-03-31 2015-10-08 積水化成品工業株式会社 光拡散体及びその用途
JPWO2015151319A1 (ja) * 2014-03-31 2017-04-13 積水化成品工業株式会社 光拡散体及びその用途
US9864110B2 (en) 2014-03-31 2018-01-09 Sekisui Plastics Co., Ltd. Light diffuser and use thereof
US20220299682A1 (en) * 2019-10-31 2022-09-22 Kimoto Co., Ltd. Light diffusion film

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