JP2012042610A - Diffusion sheet, light source unit, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diffusion sheet and a light source unit capable of reducing front luminance unevenness and oblique luminance unevenness.SOLUTION: A diffusion sheet 1 of the present invention includes: a base material 11 in a sheet shape; a haze layer 12 that is provided on one principal plane of the base material 11; and a non-transparent component ratio adjustment pattern 13 that is provided on one or the other principal plane of the base material 11. A haze value of the haze layer 12 is even and within a range of 75% to 100% on a sheet surface, and a non-transparent component ratio is uneven on the sheet surface.

Description

  The present invention relates to a diffusion sheet, a light source unit, and a liquid crystal display device used for back lighting of a liquid crystal display device or the like.

  Currently, liquid crystal display devices are used in a wide range of fields such as mobile phones, PDA terminals, digital cameras, televisions, personal computer displays, and notebook computers. In the liquid crystal display device, for example, a light source unit called a backlight unit is disposed behind the liquid crystal display panel, and an image is displayed by supplying light from the light source unit to the liquid crystal display panel.

  When the light source unit used in the liquid crystal display device is roughly classified, when the liquid crystal display panel arrangement side is set to the upper side, a direct type light source unit having a configuration in which a plurality of light sources are arranged directly under the liquid crystal display panel, and an arrangement directly under the liquid crystal panel There is an edge light type light source unit having a configuration in which a light source is arranged on the side end face of the light guide.

  The light source unit used in such a liquid crystal display device is required not only to supply uniform light to the liquid crystal display panel but also to supply as much light as possible in order to make the display image easy to see. In other words, the light source unit is required to have optical characteristics such as excellent light diffusibility and high brightness.

  By the way, in the edge light type light source unit, since the light source is arranged on the side end surface of the light guide, the light source unit itself has an advantage that it can be thinned, but the brightness is lowered by passing the light guide. Has disadvantages.

  On the other hand, the direct type light source unit has the advantage that high luminance can be obtained, but has the disadvantage that the luminance between the upper part of the light source on the liquid crystal display panel surface and the upper part between the light sources tends to be uneven. is doing. Therefore, in the direct type light source unit, an optical sheet having a function of diffusing light with a certain distance between the light source and the liquid crystal display panel, for example, a diffusion plate or a diffusion sheet is disposed between the light source and the liquid crystal panel. Like to do.

  Here, in the conventional direct type light source unit, in order to make the distribution of light incident on the liquid crystal display panel uniform over the entire panel, for example, a method of imparting an uneven shape to the diffusion plate has been used. As a method for imparting a concavo-convex shape to a diffusion plate, there are a method in which a resin is injection-molded using a mold, and a method in which a concavo-convex structure is processed into a roll with a diamond blade and is then extruded.

  Here, the mechanical unevenness forming method as described above has a problem that it takes a lot of time and the production cost is high. Further, the above-described concavo-convex forming method has a problem that the concavo-convex structure of about several tens of μm is the limit and it is not easy to improve the uniformity of the concavo-convex shape.

  On the other hand, a mold for pattern transfer is manufactured by recording irregularities on a photosensitive medium by speckles generated by laser beam interference, and a direct-type large liquid crystal display device using this mold. A hologram light guide plate (see FIG. 41 of Patent Document 1) in which irregularities are formed on the surface, which is a kind of diffusion plate used for the purpose, has been proposed. Also, a surface smooth hard layer having a Tg higher than that of the base material is laminated on one side of the base material made of a heat-shrinkable film, and the base material is heated and shrunk to form a fine wavy uneven structure. Has proposed a light diffusion sheet having a pattern printing layer on the opposite surface (Patent Document 2).

Japanese Patent Laid-Open No. 2001-23422 JP 2010-128447 A

  However, in recent years, liquid crystal display devices have become thinner, and the distance between a light source and an optical sheet (for example, the above-described hologram light guide plate or light diffusion sheet) for diffusing light from the light source is further reduced. There is a request to want. There is also a demand to reduce the number of light sources in the light source unit in order to reduce cost and power consumption.

  Here, as the ratio (p / h) between the light source pitch (p) and the light source-optical sheet distance (h) increases, that is, as h decreases (h ′ in FIG. 36A), and / or Or, as p increases (p ′ in FIG. 36B), the luminance unevenness of the backlight becomes more significant. Here, uneven brightness refers to a phenomenon in which brightness and darkness derived from the intensity distribution of the light source illuminance can be seen in the screen of the display device. When the screen is viewed from the front, the brightness unevenness when viewed from the front. It can be divided into “oblique luminance unevenness”. In the liquid crystal display device, it is required to reduce such luminance unevenness.

  The hologram light guide plate disclosed in Patent Document 1 described above cannot sufficiently reduce the front luminance unevenness and the oblique luminance unevenness, and cannot cope with the thinning of the liquid crystal display device and the reduction in the number of light sources. In the light diffusion sheet disclosed in Patent Document 2 described above, a surface smooth hard layer having a Tg higher than that of the base material is laminated on the surface, and the base material layer is heated and contracted to form a fine wavy uneven structure. Since the degree of design freedom is low and it is difficult to ensure in-plane uniformity, it is considered that the front luminance unevenness and the oblique luminance unevenness cannot be sufficiently reduced for liquid crystal display devices of different designs. .

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a diffusion sheet, a light source unit, and a liquid crystal display device capable of reducing front luminance unevenness and oblique luminance unevenness. .

  As a result of intensive studies to solve the above-described problems of the related art related to the diffusion sheet, the present inventor solved the above-described problems of the related art with the diffusion sheet having the haze layer and the non-transmission component ratio adjustment pattern. The present inventors have found that the present invention can be accomplished and have completed the present invention. The present invention is as follows.

  The diffusion sheet of the present invention is provided on a sheet-like base material, a haze layer provided on one main surface of the base material, and one main surface or the other main surface of the base material. A non-transmissible component ratio adjustment pattern, wherein the haze value of the haze layer is uniform within the sheet plane and within a range of 75% to 100%, and the non-transparent component ratio is non-uniform within the sheet plane. Features.

  In the diffusion sheet of the present invention, the haze layer is preferably a resin layer having an irregular concavo-convex pattern formed using a speckle pattern by interference exposure.

  In the diffusion sheet of the present invention, the diffusion angle of the haze layer is preferably 5 degrees to 120 degrees.

  In the diffusion sheet of this invention, it is preferable that the said haze layer contains the light-reflective ink hardened | cured material containing a light-diffusion agent.

  In the diffusion sheet of the present invention, it is preferable that the non-transmission component ratio adjustment pattern is a resin layer having an irregular concavo-convex pattern formed using a speckle pattern by interference exposure.

  In the diffusion sheet of the present invention, it is preferable that a diffusion angle of the non-transmissive component ratio adjustment pattern is 0.1 to 120 degrees.

  In the diffusion sheet of the present invention, it is preferable that the non-transmissive component ratio adjusting pattern contains a light-reflective ink cured product containing a light diffusing agent.

In the diffusion sheet of the present invention, it is preferable that the non-transmission component ratio adjustment pattern is composed of discontinuous dots, and the area of each dot is in the range of 25 to 250,000 μm ² .

  In the diffusion sheet of the present invention, the haze layer is provided on one main surface of the base material, and the non-transmissive component ratio adjustment pattern is provided on the other main surface of the base material. preferable.

  In the diffusion sheet of the present invention, it is preferable that the non-transmissive component ratio adjustment pattern is provided on one main surface of the substrate, and the haze layer is provided on the non-transmissive component ratio adjustment pattern.

  In the diffusion sheet of the present invention, in the non-transmission component ratio distribution diagram in which the horizontal axis represents the relative position in the sheet plane in a predetermined direction, and the vertical axis represents the non-transmission component ratio at the relative position in the sheet plane. It is preferable that there are a plurality of peak points indicating the peak value of the non-transmissive component ratio and a plurality of bottom points indicating the bottom value of the non-transmissive component ratio.

  In the diffusion sheet of the present invention, it is preferable that the non-transmission component rate peak point and the non-transmission component rate bottom point are alternately and periodically provided.

  The light source unit of the present invention is a light source unit including the diffusion sheet and a light source, and the diffusion sheet is configured so that incident light from the light source is in the order of the non-transmissive component ratio adjustment pattern and the haze layer. It arrange | positions so that it may permeate | transmit.

  The light source unit of the present invention preferably includes at least two of the light sources.

  In the light source unit of the present invention, the light source is preferably a linear light source.

  In the light source unit of the present invention, the light source is preferably a point light source.

  In the light source unit of the present invention, it is preferable that the period of the non-transmissive component rate adjustment pattern of the diffusion sheet and the period of the illuminance distribution on the light incident surface of the diffusion sheet are substantially equal.

  The light source unit of the present invention preferably includes a diffusion plate that is disposed between the diffusion sheet and the light source and contains a diffusing agent therein, and a reflection sheet that is disposed below the light source.

  In the light source unit of the present invention, it is preferable to include a lens sheet disposed above the diffusion sheet.

  In the light source unit of the present invention, it is preferable that a prism sheet is provided above the diffusion sheet.

  In the light source unit of this invention, it is preferable to provide the reflective polarizing sheet arrange | positioned above the said diffusion sheet.

  The liquid crystal display device of the present invention comprises a liquid crystal display panel and the light source unit that supplies light to the liquid crystal display panel.

  According to the present invention, it is possible to provide a diffusion sheet, a light source unit, and a liquid crystal display device that can effectively reduce front luminance unevenness and oblique luminance unevenness.

(A)-(c) is a schematic diagram of the diffusion sheet which concerns on embodiment of this invention. It is a cross-sectional schematic diagram showing the measuring method of the haze value of the haze layer of the diffusion sheet which concerns on embodiment of this invention. It is a cross-sectional schematic diagram showing the measuring method of the impermeable component rate of the diffusion sheet which concerns on embodiment of this invention. (A) is a figure which shows the projection area | region between the projection area | region of a linear light source which comprises the light source unit which concerns on embodiment of this invention, and a linear light source, (b) is projection of the point light source which comprises a light source unit. It is a figure which shows the projection area | region between an area | region and a point light source. It is a figure which shows distribution (one period) of the impermeable component ratio with respect to the relative position in the sheet | seat surface of the diffusion sheet which concerns on embodiment of this invention. (A)-(f) is a figure which shows distribution with respect to the relative position in the surface of the non-permeable component rate of the diffusion sheet which concerns on embodiment of this invention. It is a figure which shows an example of arrangement | positioning of the high non-permeable component rate area | region and low non-transmissive component rate area | region which concern on the diffusion sheet of embodiment of this invention. It is a figure which shows an example of arrangement | positioning of the high non-permeable component rate area | region and low non-transmissive component rate area | region which concern on the diffusion sheet of embodiment of this invention. It is a figure which shows an example of arrangement | positioning of the high non-permeable component rate area | region and the low non-transmissive component rate area | region of the diffusion sheet which concerns on embodiment of this invention. It is a figure which shows an example of arrangement | positioning of the high non-permeable component rate area | region and the low non-transmissive component rate area | region of the diffusion sheet which concerns on embodiment of this invention. (A)-(c) is a cross-sectional schematic diagram which shows an example of the diffusion sheet which concerns on embodiment of this invention. (A) is explanatory drawing of the diffusion angle of the diffusion sheet which concerns on embodiment of this invention, (b) is typical schematic which shows the transmitted light intensity when light injects from the normal line direction of a diffusion sheet FIG. (A)-(c) is a figure which shows an example of the dot density in the diffusion sheet which concerns on embodiment of this invention. (A)-(c) is a cross-sectional schematic diagram which shows an example of the diffusion sheet which concerns on embodiment of this invention. (A)-(c) is a cross-sectional schematic diagram which shows an example of the diffusion sheet which concerns on embodiment of this invention. It is a cross-sectional schematic diagram which shows an example of the diffusion sheet which concerns on embodiment of this invention. (A) is a schematic perspective view of an example of the light source unit which concerns on embodiment of this invention, (b) is a schematic perspective view of another example of the light source unit of this embodiment. (A) is a schematic perspective view of an example of the light source unit which concerns on embodiment of this invention, (b) shows the schematic perspective view of another example of a light source unit. (A) is explanatory drawing of the non-transmissive component rate period and light source space | interval in an example of the light source unit which concerns on embodiment of this invention, (b) is the non-transmissive component rate in another example of a light source unit. It is explanatory drawing of a period and a light source space | interval. It is explanatory drawing of an example of the relative positional relationship of the non-transmissive component rate distribution of the diffusion sheet which concerns on embodiment of this invention, and a light source. (A)-(c) is a schematic perspective view of the specific structure of the light source unit which concerns on embodiment of this invention. (A)-(c) is a schematic perspective view of the specific structure of the light source unit which concerns on embodiment of this invention. It is a figure which shows the example of the arrangement pattern of LED in the light source unit which concerns on embodiment of this invention. (A)-(d) is a schematic perspective view of the specific structure of the light source unit which concerns on embodiment of this invention. (A), (b) is a schematic perspective view of the specific structure of the light source unit which concerns on embodiment of this invention. It is a figure which shows the light distribution characteristic of LED used in the Example. It is a figure which shows the light distribution characteristic of LED used in the Example. It is a figure which shows the light distribution characteristic of LED used in the Example. It is an arrangement pattern figure of the LED light source in an example and a comparative example. It is a cross-sectional schematic diagram of the diffusion sheet of a comparative example. It is a figure which illustrates the shape of the dot which comprises a non-transmissive component rate adjustment pattern. It is a figure which shows distribution of the impermeable component rate of the diffusion sheet in an Example and a comparative example. It is a figure which shows distribution of the impermeable component rate of the diffusion sheet in an Example. It is a figure which shows distribution of the impermeable component rate of the diffusion sheet in an Example. It is a figure which shows distribution of the diffusion angle of the diffusion sheet in an Example and a comparative example. (A), (b) is a schematic sectional drawing of the principal part of the light source unit for demonstrating the relationship between the distance between a light source and an optical sheet, the distance between light sources, and luminance unevenness.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, in each drawing, unless otherwise specified, the positional relationship such as up, down, left, and right is based on the positional relationship shown in the drawing, and the dimensional ratio in the drawing is not limited to the illustrated ratio.

[Diffusion sheet]
The diffusion sheet of this embodiment includes a sheet-like base material, a haze layer provided on one main surface of the base material, and one main surface of the base material or the other main surface of the base material. And a non-transmission component ratio adjustment pattern. The haze value of the haze layer is uniform within the sheet plane and within a range of 75% to 100%, and the non-transmission component ratio according to the non-transmission component ratio adjustment pattern is non-uniform within the sheet plane.

  The configuration of the diffusion sheet according to the present embodiment will be described with reference to FIGS. Fig.1 (a)-(c) is a schematic diagram which shows the structural example of the diffusion sheet which concerns on this embodiment. As shown in FIGS. 1A to 1C, a diffusion sheet 1 according to this embodiment includes a base material 11 having a pair of main surfaces, and a haze layer provided on one main surface of the base material 11. 12 and a non-transmissive component ratio adjusting layer 13 provided on one main surface or the other main surface of the substrate 11. The haze layer 12 is provided so that the haze value is uniform in the sheet surface of the diffusion sheet 1. The diffusion sheet 1 has a relatively high non-transmission component rate (hereinafter referred to as “high non-transmission component rate region”, represented by A3 in the figure (see FIGS. 7 to 10)) and a relatively low region. (Hereinafter referred to as a “low non-transmission component ratio region”, which is indicated by A4 in the figure (see FIGS. 7 to 10)), and the non-transmission component ratio is not uniform within the sheet surface of the diffusion sheet 1 It is provided to become.

  As a configuration example of the diffusion sheet 1, the haze layer 12 may be provided on one main surface of the base material 11, and the non-transmissive component ratio adjusting layer 13 may be provided on the other main surface of the base material 11 (FIG. 1). (See (a)), a non-transmissive component rate adjusting layer 13 may be provided on one main surface of the substrate 11, and a haze layer 12 may be provided on the non-transmissive component rate adjusting layer 13 (FIG. 1B). The haze layer 12 may be provided on one main surface of the substrate 11, and the non-transmission component ratio adjusting layer 13 may be provided on the haze layer 12 (see FIG. 1C). The non-transmissive component ratio adjusting layer 13 may not be completely formed. As will be described later, on the at least one main surface of the base material 11, a plurality of non-transmissive component ratio adjusting layers 13 are mutually connected. It may be non-uniformly distributed so as to be spaced apart (hereinafter, the non-transmission component rate adjustment layer 13 is referred to as “non-transmission component rate adjustment pattern 13”).

  As the configuration of the diffusion sheet 1, it is preferable to provide the haze layer 12 on one main surface of the substrate 11 and provide the non-transmission component ratio adjustment pattern 13 on the other main surface. In this case, since the haze layer 12 and the non-transmission component ratio adjustment pattern 13 are disposed to face each other via the base material 11, the distance between the haze layer 12 and the non-transmission component ratio adjustment pattern 13 is increased. For this reason, the incident light transmitted and diffused through the haze layer 12 (non-transmission component rate adjustment pattern 13) is further diffused in the process of transmitting through the base material 11, and becomes the non-transmission component rate adjustment pattern 13 (haze layer 12). Therefore, the brightness unevenness suppressing effect can be exhibited more effectively.

  In addition, as a configuration of the diffusion sheet 1, a haze layer 12 (non-transmission component ratio adjustment pattern 13) and a non-transmission component ratio adjustment pattern 13 (haze layer 12) may be sequentially laminated on one main surface of the substrate 11. preferable. In this case, the non-transmission component rate adjustment pattern 13 (haze layer 12) can be physically protected by the haze layer 12 (non-transmission component rate adjustment pattern 13) laminated on the base material 11. The strength can be increased.

  In the diffusion sheet 1 of the present embodiment, the non-transmission component ratio adjustment pattern 13 is provided according to the illuminance distribution on the light incident surface of the diffusion sheet 1 so that the non-transmission component ratio is high so that the non-transmission component ratio is high. By controlling the component ratio, the transmitted light is moderated and the front luminance unevenness and the oblique luminance unevenness of the diffusion sheet 1 can be effectively reduced. That is, in the diffusion sheet 1 of the present embodiment, the haze value of the haze layer 12 is made uniform in the sheet surface, and the non-transmission component ratio adjustment pattern 13 is provided non-uniformly so as to increase or decrease the desired area in the sheet surface. By forming the transmission component rate region and the low non-transmission component rate region, it is possible to appropriately diffuse according to the illuminance distribution of the transmitted light, so that the front luminance unevenness and the oblique luminance unevenness can be effectively reduced. At this time, in the diffusion sheet 1 of the present embodiment, the haze value is uniform within the sheet surface, so that the haze is compared with the non-transmissive component rate adjustment pattern 13 formed to develop a non-uniform non-transmissive component rate. There is no need to align the layer 12, and the ease of manufacturing and the ability to reduce luminance unevenness are excellent.

  Further, the side where the haze layer 12 is provided is the light exit surface with respect to the non-transmission component ratio adjustment pattern 13 of the diffusion sheet 1, that is, the non-transmission component ratio adjustment pattern 13 is the light incident surface side and By setting the surface side, the distribution of the degree of light diffusion generated in the sheet surface of the diffusion sheet 1 by the non-transmission component ratio adjustment pattern 13 is appropriately leveled by the haze layer 12, so that the oblique luminance unevenness is effectively reduced. It can be reduced.

(Base material)
The base material 11 constituting the diffusion sheet 1 of the present embodiment is a sheet-like base material 11. The substrate 11 may be a light-transmitting substrate made of a material such as resin or glass. In particular, the light transmittance of the substrate 11 alone is preferably 75% or more. In this case, “light” is not particularly limited as long as it is visible light. For example, “light” is light emitted from a light source in a light source unit using the diffusion sheet 1 of the present embodiment.

For the light transmittance, for example, an ultraviolet-visible spectrophotometer (UV-2450, MPC-2200) manufactured by Shimadzu Corporation is used, and the base material 11 is set between the light source and the detector, and incident light at 550 nm. After detecting the intensity and transmitted light intensity, it can be calculated by the following equation (1).
Light transmittance (%) = (transmitted light intensity at 550 nm) / (incident light intensity at 550 nm) × 100 (1)

  Although the thickness of the base material 11 is not specifically limited, Usually, it exists in the range of 50 micrometers-500 micrometers. Examples of the resin material of the substrate 11 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, acrylic resins such as polymethyl methacrylate, thermoplastic resins such as polycarbonate resin, polystyrene resin, and polymethylpentene resin. Examples include resins obtained by curing an ionizing radiation curable resin composed of oligomers such as polyester acrylate, urethane acrylate, epoxy acrylate, and / or acrylate monomers with electromagnetic radiation such as ultraviolet rays or electron beams. As the glass, soda glass, borosilicate glass, or the like is used.

(Haze layer)
The haze layer 12 is a layer having a haze value of a predetermined value or more. The haze layer 12 in the diffusion sheet 1 of the present embodiment refers to a layer having a uniform haze value in the sheet surface of the diffusion sheet 1 and within a range of 75% to 100%. Specifically, the surface of a resin layer containing a diffusing agent, a light-reflective ink cured product, or a transparent resin layer is provided with a concavo-convex structure (hereinafter also referred to as “concave pattern”) to achieve a high haze value. Is exemplified.

  In the present invention, the “haze value of the haze layer” refers to a sheet in which only the haze layer 12 is laminated on one main surface of the substrate 11 so that the substrate 11 side becomes a light incident surface as shown in FIG. Then, it is determined by measuring with an apparatus conforming to JIS K 7105, for example, NDH-2000 manufactured by Nippon Denshoku. Further, the “main surface” refers to the front and back surfaces when the base material 11 is viewed as a flat surface without including the above-described thickness portion of the base material 11. When the haze layer has anisotropic scattering characteristics, the haze value may exceed 100% depending on the positional relationship between the light receiving portion of the apparatus and the main haze layer in the scattering direction. Shall be treated as In the present invention, “the haze value is uniform” means that when the haze value in the sheet surface of the diffusion sheet 1 is measured at 1 mm intervals, the measured values of all the measured points are within 5% above and below the average value. (For example, when the average value of haze values is 80%, the total measured value of haze values is within the range of 80 ± 4%). It is more preferable if the measured values at all points where the haze value is measured are within 3% of the average value.

  The haze value of the haze layer 12 is preferably 75% or more, more preferably 80% or more, further preferably 90% or more, and particularly preferably 95% or more from the viewpoint of suppressing oblique luminance unevenness.

  As the diffusing agent, fine particles made of an organic polymer or an inorganic material having an effect of diffusing light by being mixed in the resin layer, such as silicon beads and acrylic beads, can be used. Further, fine particles composed of a white pigment or an optical agent, which are components of a white ink composition described later, can also be suitably used as the diffusing agent.

  Examples of the uneven structure include a structure in which a large number of protrusions are provided on the surface. Examples of a method for forming such a concavo-convex structure include sandblasting, bead coating, and speckle pattern formation by interference exposure.

  The shape of the protrusion of the concavo-convex structure is not particularly limited, and examples thereof include a substantially conical shape, a substantially spherical shape, a substantially ellipsoidal shape, a substantially lenticular lens shape, and a substantially parabolic shape. The protrusions may be regularly arranged or irregularly arranged. Further, the protrusions may be connected by a continuous curved surface. In order to obtain favorable characteristics regarding the light diffusion performance, the height of the protrusions is preferably in the range of 1 μm to 15 μm, and the pitch is preferably in the range of 1 μm to 30 μm.

  The concavo-convex structure is preferably irregular in height and pitch from the viewpoint of suppressing moire. Further, a pseudo random structure in which irregular irregularities are connected by a continuous curved surface can also be preferably used. This pseudo-random structure is preferably a fine three-dimensional structure characterized by non-planar speckles in that a uniform haze value can be obtained despite being random. The three-dimensional structure characterized by non-planar speckle is suitable for forming a fine concavo-convex structure having a height or pitch of 10 μm or less, which has been difficult by machining.

(Non-transmissive component rate adjustment pattern)
The non-transmissive component ratio adjustment pattern 13 is provided on the base material 11 so that the non-transmissive component ratio defined below becomes a predetermined value within the sheet surface of the diffusion sheet 1. In the diffusion sheet 1 according to the present embodiment, by providing the non-transmission component ratio adjustment pattern 13 on one main surface of the base material 11 on which the haze layer 12 is laminated or the other main surface on the opposite side, a sheet surface. It is possible to provide a high non-transmission component rate region and a low non-transmission component rate region in a desired region. Thus, by providing the high non-transmission component rate region and the low non-transmission component rate region, the non-transmission component rate of the diffusion sheet 1 is adjusted to be non-uniform in the sheet plane. Specifically, as the non-transmission component ratio adjustment pattern 13, a pattern prepared by applying light-reflective ink in the form of dots on the main surface of the substrate 11, an uneven pattern provided on the surface of the transparent resin layer Is exemplified.

In the present invention, the “non-transmission component ratio” is a component other than a component that is transmitted from the diffusion sheet 1 when light from the light source enters the sheet surface of the diffusion sheet 1 (for example, a reflection component, an absorption component, a scattering component). ), And is a value obtained by subtracting the light transmittance obtained by the above-described formula (1) from 100 (%).
Non-transmissible component ratio (%) = 100−light transmittance—formula (2)

  The non-permeable component ratio of the diffusion sheet of this embodiment is preferably 10% or more and 90% or less, more preferably 10% or more and 80% or less, and further preferably 20% or more and 80% or less. . The non-transmission component ratio is preferably 90% or less from the viewpoint of suppressing a decrease in luminance, and is preferably 10% or more from the viewpoint of effectively reducing front and oblique luminance unevenness.

  The non-transmissive component ratio in the diffusion sheet 1 of the present embodiment is measured using, for example, an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation, UV-2450, MPC-2200). In the present invention, the non-transmission component ratio of the diffusion sheet 1 is measured in a state where the base material 11, the haze layer 12 and the non-transmission component ratio adjustment pattern 13 are provided. In this case, as shown in FIGS. 3A to 3C, the haze layer 12 of the diffusion sheet 1 is set in a direction farther from the light source than the non-transmissive component ratio adjustment pattern 13, and incident at a transmission wavelength of 550 nm. The light intensity and the transmitted light intensity are detected and calculated by the relational expression (1) and the relational expression (2).

  In the present invention, “the non-transmission component rate is non-uniform” means that when the non-transmission component rate in the sheet surface of the diffusion sheet 1 is measured at intervals of 1 mm, a value obtained by subtracting the minimum value from the maximum value of the measurement value. The state in which the non-permeable component ratio in the sheet surface is distributed so as to differ by 2% or more from the average value of all measured points. As described above, the non-transmission component rate is uneven, for example, by providing a high non-transmission component rate region and a low non-transmission component rate region in the sheet surface periodically or non-periodically. The difference value obtained by subtracting the minimum value of the measured value of the non-transmissive component ratio in each non-transmissive component ratio region from the maximum value of the measured value of the non-transmissive component ratio in the transparent component ratio region is A state that exceeds 2% of the average value of the measured values can be mentioned.

In order to change the non-transmission component ratio by the non-transmission component ratio adjustment pattern 13 prepared by applying light-reflecting ink in the form of dots, the density of dots in a certain area may be changed depending on the location, or the density may be constant. Then, the area of the dots may be changed, or the ink film thickness may be changed depending on the place by reapplying ink. When the pattern consists of dots, if the dots are too small, the reproducibility at the time of production becomes a problem. If the dots are too large, the dots can be visually recognized when the diffusion sheet of this embodiment is used in a liquid crystal display device. to become poor as, it is preferable area of each dot is 25 [mu] m ² or more ～250000Myuemu ² or less. When the pattern is composed of dots, as shown in FIG. 31, the dots may be circular, elliptical, square, or polygonal, such as a star shape. The outer shape of each shape may be a slightly distorted shape.

  As the light reflective ink, white ink is most preferable from the viewpoint of high reflectance and low absorption. Moreover, as a coating method, since the pattern of a white ink hardened | cured material can be formed freely, a printing method is preferable.

  Here, the white ink cured product means a product obtained by printing and curing a white ink composition. The white ink composition includes a solvent, a white pigment, a dispersant, and a resin as a fixing agent on the surface of an object. Is included as a basic component.

Specific examples of the white pigment in the white ink composition include titanium oxide (TiO ₂ , titanium white), calcium carbonate, talc, clay, aluminum silicate, basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , silver White), zinc oxide (ZnO, zinc white), strontium titanate (SrTiO ₃ , titanium strontium white), barium sulfate and the like can be used alone or in a mixed system. In particular, titanium oxide has dispersion stability because it has a lower specific gravity than other inorganic white pigments, has a high refractive index and excellent optical scattering properties, and is chemically and physically stable. Thus, since the hiding power and optical scattering property as a pigment are large, it is preferable to use titanium oxide as a main component as the inorganic white pigment used in the present invention. The white pigment can be mixed for the purpose of adjusting the color of the diffused light.

  The mixing ratio of the white pigment is preferably 30% by mass to 60% by mass of the entire white ink composition. A white pigment other than titanium oxide is generally used in an amount of up to about 30% of the entire pigment for the purpose of dispersion aid, if necessary.

  Examples of the resin in the white ink composition include ketone resin, sulfoamide resin, maleic acid resin, ester gum, xylene resin, alkyd resin, rosin, polyvinylpyrrolidone, polyvinyl butyral, acrylic resin, melamine resin, cellulose resin, and vinyl. Resins, phenol resins, ester resins and the like can be used, and among them, acrylic resins can be preferably used.

  The organic solvent in the white ink composition is used for the purpose of dissolving the resin and adjusting the viscosity, and is an aromatic hydrocarbon solvent such as toluene, xylene, ethylbenzene, n-hexane, n-heptane, isoheptane, n -An aliphatic hydrocarbon solvent such as octane or isooctane, or a cycloparaffin solvent such as methylcyclohexane or ethylcyclohexane can be used alone or in the form of a mixture. The amount of the organic solvent used is about 30% by mass to 60% by mass of the entire white ink composition.

  Moreover, you may contain the optical agent which has an optical effect in a white ink composition. Optical agents are particles having the property of diffusing light, and are roughly classified into inorganic fillers and organic fillers. As the inorganic filler, silica, aluminum hydroxide, aluminum oxide, zinc oxide, barium sulfide, magnesium silicate, or a mixture thereof can be used. As the organic filler, acrylic, acrylonitrile, non-yellowing urethane, styrene, or the like can be used. Inorganic fillers are preferable from the viewpoint of low swellability due to printing ink, and urethane fillers are preferable among organic fillers.

  The compounding amount of the optical agent is preferably 10 parts by mass or more and 80 parts by mass or less, and particularly preferably 20 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the resin in the white ink composition. If the compounding amount of the optical agent is less than the above range, the luminance uniformity effect becomes insufficient. Conversely, if the compounding amount of the optical agent exceeds the above range, the non-transmission component ratio adjustment pattern 13 is changed. This is because it becomes difficult to apply the white ink composition to be formed.

  The printing method may be a conventionally known method, and any method such as offset printing, flexographic printing, gravure printing, screen printing, ink jet printing, thermal fusion printing using a thermal transfer ribbon, and thermal sublimation printing. But you can. In particular, offset printing enables printing with clear dots, and because the plate does not touch the sheet directly and wears the cylinder, it is suitable for mass printing and can be produced in a relatively short time. It is good in terms of efficiency. In particular, gravure printing enables clear printing of halftone dots, and since the plate is metal, it is less worn and suitable for mass printing, so it is excellent in terms of design reproducibility and production efficiency. Flexographic printing has high printing stability because the printing density is stable and the printing density is relatively high, and the ink density can be controlled by adjusting the cell size of the anilox roll that mediates between the plate and the printed matter.・ Excellent in terms of high concealment and easy printing density control. Screen printing is excellent in that it can easily increase the concealment degree because the ink thickness can be increased.

  The printing ink is not particularly limited as long as it can be used for printing. For example, evaporative drying ink, oxidation polymerization ink, heat-curing ink, two-component reaction ink, ultraviolet-curing ink, heat Examples thereof include melt ink, heat sublimation ink, and the like. Among these, ultraviolet curable inks suitable for film printing are preferable. In order to improve the optical effect, the printing ink is preferably white or gray. However, a method of improving the diffusion effect by adding an inorganic filler or an organic filler to the transparent ink may be used.

  In order to change the non-transmission component ratio by the concave / convex pattern provided on the surface of the transparent resin layer, the concave / convex pattern of the same type as the concave / convex pattern constituting the haze layer described above is produced by changing the aspect ratio of the concave / convex pattern depending on the location. Can be mentioned.

  Next, with reference to FIGS. 4A and 4B, the projection area A1 of the light source (hereinafter, also referred to as “region immediately above the light source” in the figure, represented by A1) and the light source in the diffusion sheet 1 of the present embodiment. The projection area A2 (hereinafter, also referred to as “inter-light source area”, represented by A2 in the figure) will be described. 4A and 4B are plan views schematically showing the region A1 directly above the light source and the region A2 between the light sources of the diffusion sheet 1 of the present embodiment. 4A shows an example in which the diffusion sheet 1 is arranged on the cold cathode tube 14 as a light source, and FIG. 4B shows an example in which the diffusion sheet 1 is arranged on the LED 15 as a light source. Is shown.

  As shown in FIG. 4A, when the cold cathode tube 14 as a linear light source is used, a rectangular area in plan view along the line direction of the cold cathode tube 14 becomes an area A1 directly above the light source. The area outside the area A1 directly above the light source is the inter-light source area A2. In addition, as shown in FIG. 4B, when the LED 15 as a point light source is used, a circular area in plan view near the outer periphery of the LED 15 becomes the area A1 directly above the light source. The outer area is the inter-light source area A2.

  4A and 4B show an example in which the entire area within the diffusion sheet 1 is divided into two areas, an area A1 directly above the light source and an area A2 between the light sources. You may divide | segment so that areas other than area | region A1 and area | region A2 between light sources may be provided. In addition, the inter-light source region A2 may not be adjacent to the region A1 directly above the light source, and may include a region located in the middle of the adjacent cold cathode tube 14 or the LED 15.

  In general, when a light source unit is configured with two or more light sources and the diffusion sheet according to the present embodiment, the period of the illuminance distribution on the light incident surface of the diffusion sheet coincides with the period in which the light sources are arranged. In addition, the region directly above the light source and the peak portion of the illuminance distribution, and the region between the light source and the bottom portion of the illuminance distribution often coincide with each other.

  The illuminance distribution on the light incident surface of the diffusion sheet 1 of the present embodiment can be measured by, for example, EZCONTRASTXL88 manufactured by ELDIM. Specifically, in the light source unit in which the diffusion sheet 1 is provided, the omnidirectional luminance distribution is measured by setting the focal point of the apparatus at a position where the light incident surface of the diffusion sheet 1 is located, except for the diffusion sheet 1. It can be measured by repeating in the in-plane measurement target range to obtain an integrated light intensity (Integrated Intensity).

  In the diffusion sheet 1 according to the present embodiment, it is preferable that the change in the non-transmissive component ratio in the sheet surface is periodically distributed. FIG. 5 is a diagram showing an example of the distribution of the non-transmission component rate for one cycle in the diffusion sheet 1 of the present embodiment (hereinafter referred to as “non-transmission component rate distribution diagram”). In the non-transmission component ratio distribution diagram shown in FIG. 5, the horizontal axis indicates the relative position in the sheet plane in a predetermined direction within the sheet plane of the diffusion sheet 1, and the non-transmission component ratio at the relative position in the sheet plane is expressed in the vertical direction. Stay on the axis. In the diffusion sheet 1 of the present embodiment, the non-transmission component ratio of the emitted light changes when light rays are incident on the sheet surface of the diffusion sheet 1 perpendicularly. For this reason, in the non-transmission component rate distribution diagram of the diffusion sheet 1 of the present embodiment, there are a plurality of peak points indicating the peak value of the non-transmission component rate and bottom points indicating the bottom value of the non-transmission component rate (FIG. 5). Shows one peak point and two bottom points). The peak value refers to the value of the highest non-transmission component ratio in one period of the non-transmission component ratio distribution map, and the bottom value refers to the lowest non-transmission component in one period of the non-transmission component ratio distribution chart. The rate value.

  Moreover, as shown in FIG. 6, you may comprise so that a non-permeable component rate may become a pattern which changes periodically along the predetermined direction in the diffusion sheet 1 surface. In this case, it is preferable because a front and oblique luminance unevenness suppressing effect is effectively exhibited as compared with the case where there are a plurality of light sources.

  The change in the non-transmission component rate does not have to be strictly a linear shape, a curved shape, or a staircase shape. And a curved shape. 6 (a) to 6 (f), the relative position within the diffusion sheet 1 surface of the non-transmission component ratio of the diffusion sheet 1 in which the non-transmission component ratio changes to a linear shape, a curved shape, or a mixed shape of a straight line and a curved line. An example of the distribution for is shown.

  In the diffusion sheet 1, it is preferable that the high non-transmission component ratio region in the sheet surface is disposed immediately above the light source. However, when the non-transmission component ratio is extremely high as a whole, the low non-transmission component ratio region is disposed immediately above the light source. May be. Further, it is preferable that the non-transmission component ratio between the high non-transmission component ratio region and the low non-transmission component ratio region changes smoothly.

  Also, there is a bottom point of the non-transmission component rate, and the non-transmission component rate distribution in the low non-transmission component rate region including the bottom point is also a downward convex curve with the bottom value being the minimum value, reducing uneven brightness From the viewpoint of (refer FIG. 6 (a)-(d)).

  In the pattern shown in FIG. 6C, the distribution of the non-transmission component ratio includes a first section D1 having a peak shape including a peak point, and the distribution of the non-transmission component ratio includes a bottom point and protrudes downward. This pattern is particularly effective when the light source is a point light source. For example, when an LED (light emitting diode) is used as the point light source, the non-transmissive component ratio in the diffusion sheet 1 according to the present embodiment can be designed with respect to the illuminance distribution regardless of the light output angle.

  Here, the high non-transmission component rate region is a region where the non-transmission component rate is larger than the arithmetic average value of the maximum peak value and the minimum bottom value, and the low non-transmission component rate region is the maximum peak value. The area is smaller than the arithmetic average value of the minimum value and the bottom value. In one cycle, the number of peak points and bottom points is not limited to one, and a plurality of points having the same value may exist.

  Further, the non-transmission component ratio distributed between adjacent peak points and bottom points refers to the non-transmission component ratio existing in the broken line section D3 shown in FIG. That is, when there are a plurality of peak points, the non-transmission component rate existing in the section between the position corresponding to the adjacent bottom point and the position corresponding to the peak point.

  In addition, “periodically” means that the repeated patterns are compared with each other, and the peak value corresponding to the same repetition and the displacement from the start point of the period giving the peak value, and the bottom value and the bottom value are given. If the displacement from the starting point of the cycle is within a range of ± 15% (preferably within 10%, more preferably within 5%) of the average value of all the repeated patterns, it periodically changes. Shall. The direction showing the periodicity may be at least one in the surface of the diffusion sheet 1 and can be specified by creating a non-transmission component ratio distribution on the surface of the diffusion sheet 1. In the present invention, the non-transmission component rate of a plurality of repeated peak points is preferably within 10%, more preferably within 5%, the difference in the non-transmission component rate of all measured peak points, Most preferably, it is within 3%. The same applies to the bottom point.

  Next, an arrangement example of the high non-transmission component rate region A3 and the low non-transmission component rate region A4 in the diffusion sheet of the present embodiment will be described with reference to FIGS. 7-10 is explanatory drawing of the high non-permeable component rate area | region A3 and the low non-transmissive component rate area | region A4 of the diffusion sheet 1 which concerns on this Embodiment.

  In the example shown in FIG. 7, the high non-transmissive component rate region A3 and the low non-transmissive component rate region A4 are alternately changed in the cycle C1 in the x-axis direction in the surface of the diffusion sheet 1. The non-transmission component ratio in the surface of the diffusion sheet 1 has a peak value in the vicinity of the imaginary line L1 in each high non-transmission component ratio area A3, and a bottom value in the vicinity of the imaginary line L2 in each low non-transmission component ratio area A4. Become.

  In the example shown in FIG. 8, in the y-axis direction in the surface of the diffusion sheet 1, from the high non-transmission component rate region A <b> 3 on one end side of the diffusion sheet 1 toward the low non-transmission component rate region A <b> 4 on the other end side. A region A5 in which the non-transmission component rate changes, and a region A6 in which the non-transmission component rate changes from the low non-transmission component rate region A4 on one end side of the diffusion sheet 1 toward the high non-transmission component rate region A3 on the other end side. Are alternately changed in the cycle C1.

  That is, in the example shown in FIGS. 7 and 8, it is shown that the non-transmissive component ratio is periodically changed as shown in FIG. 5 in the x-axis direction in the surface of the diffusion sheet 1. Such a pattern is preferably used for a line light source, but is also used for a point light source in some cases.

  In the example shown in FIG. 9, a circular high non-transmission component rate region A3 is provided in a lattice pattern at a predetermined period C2 in the surface of the diffusion sheet 1, and the low non-transmission component rate region A3 is low. There is a non-transmissive component ratio region A4. The non-transmissive component ratio in the surface of the diffusion sheet 1 has a peak value in the vicinity of the center point P1 of each high non-transmissive component ratio region A3, and a bottom value in each low non-transmissive component ratio region A4. That is, in the reflection sheet 1 shown in FIG. 9, the high non-transmission component rate region A3 and the low non-transmission component rate region A4 periodically exist in the x-axis direction and the y-axis direction in the surface of the diffusion sheet 1.

  Further, in the example shown in FIG. 10, circular high non-transmission component ratio regions A <b> 3 are provided in a staggered pattern in the surface of the diffusion sheet 1. In the example shown in FIG. 10, the high non-transmission component ratio region A3 is provided with a predetermined period C2 in the x-axis direction and is provided with the period C3 in the y-axis direction. A low non-transmission component ratio region A4 exists between them. The non-transmissive component ratio in the surface of the diffusion sheet 1 has a peak value in the vicinity of the center point P1 of each high non-transmissive component ratio region A3, and a bottom value in each low non-transmissive component ratio region A4. That is, in the diffusion sheet shown in FIG. 10, the high non-transmission component rate region A3 and the low non-transmission component rate region A4 periodically exist in the x-axis direction and the y-axis direction in the surface of the diffusion sheet 1.

  Also in the examples shown in FIGS. 9 and 10, the non-transmission component ratio changes as shown in FIG. 5 in the cross sections in the x-axis direction and the y-axis direction in the surface of the diffusion sheet 1. Such a pattern is preferably used for a point light source, but may be used for a line light source in some cases.

  Hereinafter, a specific configuration example of the diffusion sheet 1 according to the present embodiment will be described.

(First embodiment)
In the diffusion sheet according to the first embodiment of the present invention (hereinafter referred to as “first embodiment”), the haze layer is a resin layer having an irregular concavo-convex pattern formed using a speckle pattern by interference exposure. The non-transmission component ratio adjustment pattern is a pattern made of a light-reflective ink cured product containing a light diffusing agent.

  If the haze layer is composed of an irregular concavo-convex pattern formed using a speckle pattern by interference exposure, diffusion due to the surface structure can be used, resulting in high transmittance and high haze, and the desired brightness unevenness suppression effect is further improved. This is preferable in that it can be realized with high luminance. In addition, when the non-transmission component ratio adjustment pattern is composed of a pattern made of a light-reflective ink containing a light diffusing agent, a high reflectance can be obtained, and a higher luminance unevenness suppressing effect can be obtained. Is preferable.

  Next, a configuration example of the diffusion sheet according to the first embodiment will be described with reference to FIGS. Fig.11 (a)-(c) is a schematic diagram which shows the structural example of the diffusion sheet of a 1st form.

  Fig.11 (a)-FIG.11 (c) are the schematic diagrams of the diffusion sheet 20 which concerns on a 1st form. As shown in FIGS. 11A to 11C, the diffusion sheet 20 according to the first embodiment is provided on a sheet-like base material 21 and one main surface of the base material 21, and has a haze value. It has a uniform haze layer 22 and a non-transmission component ratio adjustment pattern 23 provided on one main surface side or the other main surface side of the substrate 21. The haze layer 22 is a resin layer having an irregular concavo-convex pattern formed using a speckle pattern formed by interference exposure, and is provided as a concavo-convex pattern that covers one main surface of the substrate 21. The non-transmissive component ratio adjustment pattern 23 is provided as a pattern made of a light-reflective ink cured product containing a light diffusing agent. A plurality of non-transmission component ratio adjustment patterns 23 may be provided on the other main surface of the base material 21 so as to be separated from each other (see FIG. 11A). A plurality may be provided so as to be separated from each other between the material 21 and the haze layer 22 (see FIG. 11B), or a plurality may be provided so as to be separated from each other on the surface of the haze layer 22 (see FIG. 11C). )reference).

  By providing the haze layer 22 on one main surface of the base material 21 and providing the non-transmission component ratio adjustment pattern 23 on the other main surface of the base material 21, the gap between the haze layer 22 and the non-transmission component ratio adjustment pattern 23 is set. This is preferable in that each brightness unevenness suppressing effect can be further exhibited. Further, when the haze layer 22 and the non-transmission component ratio adjustment pattern 23 are laminated on one main surface of the substrate 21, the haze layer 22 (non-transmission component ratio adjustment pattern 23) is replaced with the non-transmission component ratio adjustment pattern 23 ( This is preferable in that the haze layer 22) can be physically protected and the strength can be increased. In particular, when the non-transmission component rate adjustment pattern 23 is provided on the base material 21 and further the haze layer 22 is provided thereon, the pattern of the light-reflective ink cured product constituting the non-transmission component rate adjustment pattern 23 is obtained. Since it can be physically protected by the haze layer 22 composed of a concavo-convex structure, it is preferable in that the restrictions on the mechanical strength of the light-reflective ink cured product can be reduced and the options can be expanded.

  The haze value of the haze layer 22 in the first embodiment is preferably 75% or more, more preferably 92% or more, further preferably 95% or more, and particularly preferably 97% or more from the viewpoint of suppressing oblique luminance unevenness. The diffusion angle of the haze layer 22 composed of a resin layer having an irregular concavo-convex pattern formed using a speckle pattern is preferably 5 degrees or more and 120 degrees or less. In order to effectively suppress oblique luminance unevenness, the haze value of the haze layer is preferably high, and the haze value increases as the diffusion angle increases. Therefore, the diffusion angle of the haze layer should be 20 degrees or more and 120 degrees or less. More preferably, it is 40 ° or more and 120 ° or less, and particularly preferably 60 ° or more and 120 ° or less.

  In the present invention, the “diffusion angle” refers to an angle (FWHM: Full Width Half Maximum) that is twice the angle (half-value angle) at which the transmitted light intensity attenuates to half of the peak intensity (see FIG. 12A). . This diffusion angle is, for example, from Phonon's Goniometric Radiometers Real-Time Far-Field Angular Profiles Model LD8900 (hereinafter referred to as “LD8900”), from the normal direction of the uneven surface of the diffusion sheet 20 from the uneven surface side. It can be determined by measuring the angular distribution of transmitted light intensity with respect to incident light. Here, the normal direction of the diffusion sheet 20 refers to the direction shown in FIG. The diffusion angle of the haze layer 22 is measured by making light incident from the haze layer 22, that is, the resin layer side having the concavo-convex pattern, with the configuration of only the base material 21 and the haze layer 22.

  Moreover, in the haze layer 22 of the diffusion sheet 20 of the first embodiment, an irregular uneven pattern formed using a speckle pattern by interference exposure is an isotropic method in which substantially the same diffusion angle is obtained regardless of the measurement direction. Both an anisotropic concavo-convex pattern and an anisotropic concavo-convex pattern having different diffusion angles depending on the measurement direction can be used. An anisotropic uneven | corrugated pattern is an uneven | corrugated pattern from which a diffusion angle differs, for example, when a diffusion angle is measured in two orthogonal directions. In the case of an anisotropic concavo-convex pattern, when the diffusion angle in the most diffusing direction is A degree and the diffusion angle in the least diffusing direction is B degree, the diffusion angle is expressed as “A degree × B degree”. Note that the preferable diffusion angle range when the haze layer is an anisotropic concavo-convex pattern refers to a preferable diffusion angle range of the diffusion angle in the most diffusing direction.

  Specifically, the diffusion sheet 20 having the uneven pattern on its surface can be manufactured as follows. First, a sub-master type in which a desired speckle pattern is formed by irradiating a photosensitive material or a photoresist with laser light through a lens or a mask in advance by interference exposure. By changing the distance and size between the members constituting the laser irradiation system and adjusting the size, shape and direction of the speckle pattern, the range of the diffusion angle can be controlled and the concavo-convex structure having different diffusion angles can be recorded. .

  In general, the range of the diffusion angle depends on the average size and shape of the speckle. If speckle is small, the angle range is wide. Further, the unit structure of the concavo-convex structure is not limited to an isotropic one, and an anisotropic one can be formed, or a concavo-convex structure in which both are combined can be obtained. If the speckle is an oval in the horizontal direction, the shape of the angular distribution is an oval in the vertical direction. In this way, a speckle pattern is determined according to a desired directivity angle and diffusion angle, and a submaster mold having the diffusion angle is manufactured. A metal is deposited on the sub-master mold by a method such as electroforming, and a speckle pattern is transferred to the metal to produce a master mold. A detailed manufacturing method of this sub-master type is disclosed in Japanese Patent No. 3341519. All this content is included here. A speckle pattern is transferred to the light extraction surface of the photocurable resin layer by forming the photocurable resin layer with ultraviolet rays using the master mold.

  The unevenness height of the surface structure can be judged from, for example, the pitch, aspect ratio, surface roughness, etc. of the cross-sectional shape of the light reflecting sheet observed with a scanning electron microscope. Further, the pitch, aspect ratio, surface roughness, and the like can be read from the observation image of the light reflecting sheet surface by a laser confocal microscope. For example, as the pitch is shorter, the aspect ratio is larger, or the surface roughness is larger, it can be considered that the unevenness height is higher.

  The non-transmission component ratio adjustment pattern 23 can be configured, for example, by applying a light reflective material over the entire main surface of the base material 21 or partially. Examples of such light-reflective materials include light-reflective inks such as paints and metal pastes, light diffusing agents such as silicon beads and acrylic beads, light absorbers such as fluorescent brighteners, surface irregularities, organic / inorganic A filler etc. are raised and the transmittance | permeability and a reflectance can be controlled by the area, thickness, density, etc. which the light reflective material occupies in a main surface. Among these, light reflective ink is preferable from the viewpoint that the transmittance and reflectance can be easily controlled and the area can be increased, and white ink is most preferable from the viewpoint of high reflectance and low absorption. . Moreover, as a coating method, since the pattern of a white ink hardened | cured material can be formed freely, a printing method is preferable. The white ink cured product and the printing method are as described above.

  The non-permeable component ratio of the diffusion sheet of the first form is preferably 10% or more and 90% or less, more preferably 10% or more and 80% or less, and further preferably 20% or more and 80% or less. The non-transmission component ratio is preferably 90% or less from the viewpoint of suppressing a decrease in luminance, and is preferably 10% or more from the viewpoint of effectively reducing front and oblique luminance unevenness.

  The distribution of the non-transmissive component ratio can be generated by the distribution of the dot density and the dot density in the pattern made of dots formed of the light-reflecting ink cured product.

The dot density of the light-reflective ink cured product is a normal line with respect to the main surface of the substrate 21 at a portion where the light-reflective ink cured product and the substrate 21 are in contact as shown in the following relational expression (3) It refers to the percentage of the value obtained by dividing the area observed from the direction (hereinafter referred to as “ink area”) by the observed unit area. The ink area can be measured with, for example, an ultra-deep color 3D shape measurement microscope (VK-9500) manufactured by Keyence Corporation or an optical microscope. As the dot density increases, the reflectance at that portion increases and the transmittance decreases.
Dot density (%) = (ink area) / (observed unit area) × 100 (3)

  The dot density of the light-reflective ink cured product is governed by the ink density (ratio of the light reflection component in the ink cured product) and the dot thickness on an arbitrary surface. In this case, since the concentration of the light reflection component in the ink composition is known in advance, the concentration can be grasped every time the type of ink is changed. The dot thickness can be measured with, for example, an ultra-deep color 3D shape measurement microscope (manufactured by Keyence Corporation, VK-9500). Here, the dot thickness represents the dot thickness after the solvent component such as water or solvent is volatilized, for example, when the ink is a water-containing ink or a solvent-containing ink. As the dot density increases, the reflectance at that portion increases and the transmittance decreases.

  The distribution of the non-transmission component ratio is formed by changing the dot density while keeping the dot density of the non-transmission component adjustment ratio pattern 23 (light-reflective ink cured product), that is, “dot thickness” and “ink density” constant. However, it is preferable from the viewpoint that the distribution of light transmittance can be easily controlled. FIGS. 13A to 13C are diagrams illustrating an example of dot density in the diffusion sheet 20 according to the first embodiment. In changing the dot density of the diffusion sheet 20, the pitch P between dots is made constant, and the dot area of each non-transmissive component ratio adjustment pattern 23 (light-reflective ink cured product) is reduced as the dot density decreases. (FIG. 13A). In addition, the dot area of each non-transmissive component ratio adjustment pattern 23 (light-reflective ink cured product) is made constant, and the pitch of each non-transmissive component ratio adjustment pattern 23 (light-reflective ink cured product) is reduced as the dot density decreases. P may be increased (FIG. 13B). Further, as the dot density decreases, the dot area of each non-transmissive component ratio adjustment pattern 23 (light-reflective ink cured product) may be reduced and the pitch P may be increased. (Fig. 13 (c))

  The non-transmission component rate adjustment pattern 23 (dot pattern of the light-reflective ink cured product) may be prepared once or may be prepared in a plurality of times. In that case, adjacent dots may overlap each other in a portion where the dot density is high.

Next, a method for manufacturing the diffusion sheet 20 according to the first embodiment will be described.
In the diffusion sheet 20 shown in FIG. 11A, after forming the haze layer 22 on one main surface of the base material 21, the non-transmissive component ratio adjustment pattern 23 is printed on the other main surface of the base material 21. The haze layer 22 may be formed on the other main surface of the base material 21 after the non-transmission component ratio adjustment pattern 23 is printed on one main surface of the base material 21, or non-transmission The component ratio adjustment pattern 23 and the haze layer 22 may be formed simultaneously. By manufacturing in this way, a haze layer 22 made of a resin layer having an irregular concavo-convex pattern formed using a speckle pattern by interference exposure, and a non-transmissive component rate adjustment pattern made of a light-reflective ink cured product 23 are respectively provided on the pair of main surfaces of the base material 21. For this reason, since the distance between the haze layer 22 and the non-transmission component ratio adjustment pattern 23 becomes large, it is preferable at the point which can exhibit each brightness nonuniformity suppression effect more.

  Moreover, the diffusion sheet 20 shown in FIG.11 (b) prints the non-transmissive component rate adjustment pattern 23 which consists of a light-reflective ink cured material on the one main surface of the base material 21, and also by interference exposure on it. It can manufacture by providing the haze layer 22 which consists of a resin layer which has the irregular uneven | corrugated pattern formed using the speckle pattern. In this way, the non-transmission component rate adjustment pattern 23 made of a light-reflective ink cured product is provided on one main surface of the base material 21, and the irregular pattern formed by using the speckle pattern by interference exposure is further formed thereon. When the haze layer 22 made of a resin layer having a concavo-convex pattern is provided, the light-reflective ink pattern constituting the non-transmissive component ratio adjustment pattern 23 can be physically protected by the haze layer 22 constituted by the concavo-convex structure. For this reason, it is preferable in that the mechanical strength of the light-reflective ink is reduced and the options can be expanded.

  Similarly, the diffusion sheet 20 shown in FIG. 11C is a haze layer made of a resin layer having an irregular concavo-convex pattern formed on one main surface of the base material 21 using a speckle pattern by interference exposure. 22, and a non-transmissive component ratio adjusting pattern 23 made of a light-reflective ink cured product is printed thereon.

  In the case of the configuration of the diffusion sheet 20 as shown in FIGS. 11B and 11C, the other main surface opposite to the main surface on which the non-transmission component ratio adjustment pattern 23 and the haze layer 22 are provided is a smooth surface and an uneven surface. Or a matte surface. From the viewpoint of improving the luminance and reducing the luminance unevenness, it is preferable that the surface opposite to the surface having the concavo-convex structure is a smooth surface. In general, when a diffusion sheet is laminated, a very small amount of beads may be applied to the surface opposite to the surface having the concavo-convex structure as long as smoothness is not lost in order to prevent damage. Such a case is also included in the smooth surface.

(Second Embodiment)
In the diffusion sheet according to the second embodiment of the present invention (hereinafter referred to as “second embodiment”), the haze layer is composed of a layer made of a light-reflective ink-cured material containing a light diffusing agent, and is a non-transmissive component. The rate adjustment pattern is composed of a resin layer having an irregular concavo-convex pattern formed using a speckle pattern by interference exposure.

  It is preferable that the haze layer is composed of a layer made of a light-reflective ink-cured material containing a light diffusing agent, because a particularly good oblique luminance unevenness suppressing effect can be obtained by high diffusion performance. In addition, when the non-transmission component ratio adjustment pattern is constituted by a resin layer having an irregular uneven pattern formed using a speckle pattern by interference exposure, reflection by the surface structure can be used, so that the high transmittance is obtained. This is preferable in that a desired luminance unevenness suppressing effect can be realized with higher luminance.

  Next, a configuration example of the diffusion sheet according to the second embodiment will be described with reference to FIGS. FIGS. 14A to 14C are schematic views illustrating a configuration example of the diffusion sheet of the second form.

  As shown in FIGS. 14A to 14C, the diffusion sheet 25 of the second form is provided on the sheet-like base material 26 and one main surface side or the other main surface side of the base material 26. The haze layer 27 having a uniform haze value and the non-transmission component ratio adjustment pattern 28 provided on one main surface of the substrate 26 and having an uneven pattern. In the diffusion sheet 25 according to the second embodiment, the haze layer 27 is provided so as to cover the other main surface of the base material 26, and the non-transmission component ratio adjustment pattern 28 is provided on the one main surface of the base material 26. Well (see FIG. 14 (a)), a non-transmission component ratio adjustment pattern 28 is provided on one main surface of the substrate 26, and a plurality of the non-transmission component ratio adjustment patterns 28 are separated from each other on the surface of the non-transmission component ratio adjustment pattern 28. A haze layer 27 may be provided (see FIG. 14B). The haze layer 27 is provided so as to cover one main surface of the substrate 26, and the non-transmission component ratio adjustment pattern 28 is provided on the haze layer 27. (See FIG. 14C).

  If the haze layer 27 and the non-transmission component ratio adjustment pattern 28 are respectively provided on the pair of main surfaces of the base material 26, the distance between the haze layer 27 and the non-transmission component ratio adjustment pattern 28 increases, and thus each luminance unevenness. The haze layer 27 and the non-transmission component ratio adjustment pattern 28 are preferably laminated on one main surface of the base material 26, so that the haze layer 27 (non-transmission component ratio adjustment pattern 28) is not used. The transmission component rate adjustment pattern 28 (the haze layer 27) can be physically protected, which is preferable in that the strength can be increased. In particular, when the haze layer 27 is provided on the substrate 26 and the non-transmissive component ratio adjustment pattern 28 is further provided thereon, the pattern of the diffusible ink constituting the haze layer 27 is made non-transmissive having a concavo-convex structure. Since it can be physically protected by the component ratio adjustment pattern 28, it is preferable in that it can reduce the restrictions on the mechanical strength of the diffusible ink and expand the options.

  The haze value of the haze layer in the second embodiment is preferably 75% or more, more preferably 80% or more, further preferably 90% or more, and particularly preferably 95% or more from the viewpoint of suppressing oblique luminance unevenness.

  In addition, in the diffusion sheet 25 of the second embodiment, the irregular uneven pattern formed using the speckle pattern by interference exposure constituting the non-transmissive component ratio adjustment pattern 28 has substantially the same diffusion angle regardless of the measurement direction. Both an isotropic concavo-convex pattern from which the angle is obtained and an anisotropic concavo-convex pattern having different diffusion angles depending on the measurement direction can be used. An anisotropic uneven | corrugated pattern is an uneven | corrugated pattern from which a diffusion angle differs, for example, when a diffusion angle is measured in two orthogonal directions.

  The non-permeable component ratio of the diffusion sheet of the second form is preferably 10% or more and 90% or less, more preferably 10% or more and 80% or less, and further preferably 20% or more and 80% or less. The non-transmission component ratio is preferably 90% or less from the viewpoint of suppressing a decrease in luminance, and is preferably 10% or more from the viewpoint of effectively reducing front and oblique luminance unevenness. The diffusion angle of the concavo-convex structure constituting the non-transmissive component ratio adjustment pattern is preferably 0.5 degrees or more and 120 degrees or less, more preferably 5 degrees or more and 100 degrees or less from the viewpoint of easy manufacture. More preferably, it is 10 degrees or more and 90 degrees or less.

  The non-transmissive component ratio of the non-transmissive component ratio adjustment pattern 28 can be adjusted by changing the diffusion angle of the concavo-convex pattern. The higher the diffusion angle, the higher the non-transmission component rate, and the lower the diffusion angle, the lower the non-transmission component rate.

  The diffusion sheet 25 having this uneven structure on the surface and having the non-transmission component ratio changing according to the region on the diffusion sheet 25 can be specifically manufactured as follows. First, a sub-master type in which a speckle pattern is formed so that a non-transmission component ratio changes depending on the position by irradiating a photosensitive material or a photoresist with a laser beam through a lens or a mask in advance by interference exposure. By controlling the size, shape and direction of the speckle pattern by changing the distance and size between the components constituting the laser irradiation system, the range of the non-transmission component ratio is controlled, and the concavo-convex structure having different non-transmission component ratios is recorded. can do.

  In general, the range of the non-transmission component ratio, that is, the range of the diffusion angle depends on the average size and shape of the speckle. If speckle is small, the angle range is wide. Further, the unit structure of the concavo-convex structure is not limited to an isotropic one, and an anisotropic one can be formed, or a concavo-convex structure in which both are combined can be obtained. If the speckle is an oval in the horizontal direction, the shape of the angular distribution is an oval in the vertical direction. In this way, a sub-master type in which the concavo-convex structure changes depending on the position is manufactured. A metal is deposited on the sub-master mold by a method such as electroforming, and a speckle pattern is transferred to the metal to produce a master mold. A speckle pattern is transferred to the light extraction surface of the photocurable resin layer by forming the photocurable resin layer with ultraviolet rays using the master mold. A detailed manufacturing method of this diffusion sheet in which the diffusion angle is changed depending on the position is disclosed in JP-T-2003-525472 (International Publication No. 01/065469). Specifically, a light source, a mask provided with a size and shape variable opening provided in an optical path of light projected from the light source, a plate for recording a diffusion pattern generated by the light projected from the light source, Using a diffuser plate that diffuses light disposed between the mask and the plate, and a blocker provided between the diffuser plate and the plate to block part of the light, the size and shape of the mask opening and blocker, It is made by changing the diffusion degree of the diffusion plate and the distance between the constituent members.

The diffusion sheet 25 of the second form is manufactured by the following process, for example.
1. By making the mask opening shape vertically long, the shape of the bottom surface of the convex portion recorded on the plate is made into a horizontally long ellipse, and a region having a vertically long elliptical diffusivity (diffusing angles in two orthogonal directions are different) is formed. To do.
2. By making the mask opening shape square, the shape of the bottom surface of the convex portion recorded on the plate is isotropic, and a region showing isotropic diffusion ability (the diffusion angle is the same in all directions) is formed.
If a periodic pattern is formed by combining the patterns 1 and 2, the light reflecting sheet according to the present embodiment, that is, the diffusion sheet 25 whose diffusion angle periodically changes in the plane can be manufactured.

  The unevenness height of the surface structure can be determined from, for example, the pitch, aspect ratio, surface roughness, etc. of the cross-sectional shape of the diffusion sheet 25 observed with a scanning electron microscope. Further, the pitch, aspect ratio, surface roughness, and the like can be read from an observation image on the surface of the diffusion sheet 25 by a laser confocal microscope. For example, as the pitch is shorter, the aspect ratio is larger, or the surface roughness is larger, it can be considered that the unevenness height is higher.

  The haze layer 27 of the diffusion sheet 25 of the second form can be configured, for example, by applying a light diffusing material to the base material. Examples of such light diffusive materials include light reflective inks such as paints and metal pastes, light diffusing agents such as silicon beads and acrylic beads, light absorbers such as fluorescent whitening agents, surface irregularities, and organic / inorganic. A filler or the like is raised, and the haze value can be controlled by the thickness, density, and the like of the light diffusing material in the haze layer 27. Among these, light reflective ink is preferable from the viewpoint that the haze value can be easily controlled and the area can be increased, and white ink is most preferable from the viewpoint of high reflectance and low absorption. Moreover, as a coating method, since a white ink hardened | cured material layer can be apply | coated uniformly, a coating method is preferable. The white ink cured product and the printing method are as described above.

Next, the manufacturing method of the structure of the diffusion sheet of a 2nd form is demonstrated.
In the diffusion sheet 25 shown in FIG. 14A, after coating the haze layer 27 on one main surface of the base material 26, the non-transmissive component ratio adjustment pattern 28 is transferred to the other main surface of the base material 26. The non-transmission component ratio adjustment pattern 28 may be transferred to one main surface of the base material 26 and then the haze layer 27 may be coated on the other main surface of the base material 26. The component ratio adjustment pattern 28 and the haze layer 27 may be formed simultaneously. Thus, the haze layer 27 made of a light-reflective ink cured product, and the non-transmission component ratio adjustment pattern 28 made of a resin layer having an irregular concavo-convex pattern formed using a speckle pattern by interference exposure, When provided on each of the pair of main surfaces of the base material 26, the distance between the haze layer 27 and the non-transmittance component adjustment pattern 28 increases, so that the luminance unevenness suppressing effect of the haze layer 27 and the non-transmittance component This is preferable in that the luminance unevenness suppressing effect of the adjustment pattern 28 can be further exhibited.

  The diffusion sheet 25 shown in FIG. 14B has a non-transmission component ratio adjustment pattern 28 by a resin layer having an irregular concavo-convex pattern formed on one main surface of the substrate 26 using a speckle pattern by interference exposure. And a haze layer 27 made of a light-reflective ink cured product is further coated thereon.

  Similarly, in the diffusion sheet 25 shown in FIG. 14 (c), a haze layer 27 made of a light-reflective ink is coated on one main surface of a substrate 26, and speckles by interference exposure are further formed thereon. It can be manufactured by providing the non-transmissive component ratio adjusting pattern 28 with a resin layer having an irregular uneven pattern formed by using a pattern. As described above, the haze layer 27 made of the light-reflective ink cured product is provided on the base material 26, and further, the resin layer has an irregular concavo-convex pattern formed using a speckle pattern by interference exposure. When the non-transmission component ratio adjustment pattern 28 is provided, the pattern of the light-reflective ink that constitutes the haze layer 27 can be physically protected by the non-transmission component ratio adjustment pattern 28 that is configured by an uneven structure. For this reason, it is preferable in that the mechanical strength of the light-reflective ink is reduced and the options can be expanded.

  In the case of the configuration as shown in FIGS. 14B and 14C, the other principal surface opposite to the one principal surface on which the non-transmission component ratio adjustment pattern 28 and the haze layer 27 are provided is a smooth surface, an uneven surface, and a mat surface. It may be. From the viewpoint of improving the luminance and reducing the luminance unevenness, it is preferable that the surface opposite to the surface having the concavo-convex structure is a smooth surface. In general, when a diffusion sheet is laminated, a very small amount of beads may be applied to the surface opposite to the surface having the concavo-convex structure as long as smoothness is not lost in order to prevent damage. Such a case is also included in the smooth surface.

(Third embodiment)
In the diffusion sheet according to the third embodiment (hereinafter referred to as “third embodiment”) of the present invention, the haze layer is composed of a layer made of a light-reflective ink cured product containing a light diffusing agent, and is a non-transmissive component. The rate adjusting pattern is constituted by a pattern made of a light-reflecting ink cured product containing a light diffusing agent.

  It is preferable that the haze layer is composed of a layer made of a light-reflective ink-cured material containing a light diffusing agent, because a particularly good oblique luminance unevenness suppressing effect can be obtained by high diffusion performance. In addition, when the non-transmission component ratio adjustment pattern is composed of a pattern made of a light-reflective ink cured product containing a light diffusing agent, a high reflectance can be obtained and a higher luminance unevenness suppressing effect can be obtained. Is preferable.

  Next, a configuration example of the diffusion sheet 30 according to the third embodiment will be described with reference to FIGS. FIGS. 15A to 15C are schematic diagrams illustrating a configuration example of the diffusion sheet 30 according to the third embodiment.

  As shown in FIGS. 15A to 15C, the diffusion sheet 30 of the third form is provided on a sheet-like base material 31 and the surface of the base material 31, and the haze layer 32 has a uniform haze value. And a non-transmission component ratio adjustment pattern 33 provided on one main surface or the other main surface of the substrate 31. In the diffusion sheet 30 according to the third embodiment, a haze layer 32 is provided so as to cover one main surface of the substrate 31, and a plurality of non-transmissive components are separated from each other on the other main surface of the substrate 31. The rate adjustment pattern 33 may be provided (see FIG. 15A). On one main surface of the base material 31, a plurality of non-transmission component rate adjustment patterns 33 are provided so as to be separated from each other, and this non-transmission component The haze layer 32 may be provided so as to cover one main surface of the base material 31 including the rate adjustment pattern 33 (see FIG. 15B), and the haze layer 32 so as to cover one main surface of the base material 31. And a plurality of non-transmissive component ratio adjustment patterns 33 may be provided on the surface of the haze layer 32 so as to be separated from each other (see FIG. 15C).

  When the haze layer 32 and the non-transmission component ratio adjustment pattern 33 are respectively provided on the pair of main surfaces facing the base material 31, the distance between the haze layer 32 and the non-transmission component ratio adjustment pattern 33 increases. The brightness unevenness suppressing effect of the layer 32 and the brightness unevenness suppressing effect of the non-transmission component ratio adjustment pattern 33 are preferable in that the haze layer 32 and the non-transmission component ratio adjustment pattern 33 are formed as one of the base materials 31. Lamination on the surface is preferable in that the haze layer 32 (non-transmission component ratio adjustment pattern 33) can be physically protected by the non-transmission component ratio adjustment pattern 33 (haze layer 32), and the strength can be increased. In particular, when the non-transmissive component rate adjustment pattern 33 is provided on the base material 31 and further the haze layer 32 is provided thereon, the pattern of the diffusible ink constituting the non-transmissive component rate adjustment pattern 33 is configured from a concavo-convex structure. Since it can be physically protected by the haze layer 32, the mechanical strength of the diffusible ink is reduced, which is preferable in terms of expanding options.

  The haze value of the haze layer in the third embodiment is preferably 75% or more, more preferably 80% or more, further preferably 90% or more, and particularly preferably 95% or more from the viewpoint of suppressing oblique luminance unevenness.

The non-permeable component ratio of the diffusion sheet of the third form is preferably 10% or more and 90% or less, more preferably 10% or more and 80% or less, and further preferably 20% or more and 80% or less. The non-transmission component ratio is preferably 90% or less from the viewpoint of suppressing a decrease in luminance, and is preferably 10% or more from the viewpoint of effectively reducing front and oblique luminance unevenness.
The material and manufacturing method of the haze layer 32 are the same as in the second embodiment. Further, the material and creation method of the non-transmission component ratio adjustment pattern are the same as those in the first embodiment.

Next, the manufacturing method of the diffusion sheet 30 of the 3rd form is demonstrated.
In the diffusion sheet 30 shown in FIG. 15A, after coating the haze layer 32 on one main surface of the base material 31, the non-transmissive component ratio adjustment pattern 33 is printed on the other main surface of the base material 31. It may be manufactured, or the non-transmission component ratio adjustment pattern 33 may be printed on one main surface of the base material 31 and then the haze layer 32 may be coated on the other main surface of the base material 31. The component ratio adjustment pattern 33 and the haze layer 32 may be formed simultaneously. As described above, the haze layer 32 made of the light-reflective ink cured product and the non-transmission component ratio adjustment pattern 33 composed of the pattern made of the light-reflective ink cured product are formed on the pair of main surfaces of the substrate 31. When each is provided, the distance between the haze layer 32 and the non-transmission component ratio adjustment pattern 33 increases. For this reason, it is preferable at the point which the brightness nonuniformity suppression effect of the haze layer 32 and the brightness nonuniformity suppression effect of the non-transmissive component rate adjustment pattern 33 are exhibited more effectively.

  Moreover, the diffusion sheet 30 shown in FIG.15 (b) prints the non-transmissive component rate adjustment pattern 33 which consists of a light-reflective ink cured material on the one main surface of the base material 31, and also light-reflects on it. It can manufacture by coating the layer which consists of ink hardened | cured materials, and providing the haze layer 32. FIG. As described above, when the non-transmission component rate adjustment pattern 33 composed of the pattern made of the light-reflective ink cured product is provided on the base material 31, and the haze layer 32 made of the light-reflective ink cured product is further provided thereon, The light-reflective ink pattern constituting the non-transmissive component ratio adjustment pattern 33 can be physically protected by the haze layer 32. For this reason, it is preferable in that the mechanical strength of the light-reflective ink is reduced and the options can be expanded.

  Similarly, in the diffusion sheet 30 shown in FIG. 15 (c), a haze layer 32 is provided by coating a layer made of a light-reflective ink on one main surface of the base material 31, and light reflection is further performed thereon. It can manufacture by printing the impermeable component ratio adjustment pattern 33 which consists of a property ink cured material.

  15B and 15C, the other main surface opposite to the main surface on which the non-transmission component ratio adjustment pattern 33 and the haze layer 32 are provided is a smooth surface, an uneven surface, a mat surface, and the like. There may be. From the viewpoint of improving the luminance and reducing the luminance unevenness, it is preferable that the surface opposite to the surface having the concavo-convex structure is a smooth surface. In general, when a diffusion sheet is laminated, a very small amount of beads may be applied to the surface opposite to the surface having the concavo-convex structure as long as smoothness is not lost in order to prevent damage. Such a case is also included in the smooth surface.

(Fourth embodiment)
In the diffusion sheet according to the fourth embodiment (hereinafter referred to as “fourth embodiment”) of the present invention, both the haze layer and the non-transmission component ratio adjustment pattern are formed using a speckle pattern by interference exposure. It is comprised by the resin layer which has an irregular uneven | corrugated pattern.

  If both the haze layer and the non-transmission component ratio adjustment pattern are constituted by a resin layer having an irregular concavo-convex pattern formed using a speckle pattern by interference exposure, diffusion and reflection by the surface structure can be used, It is preferable in that a high transmittance and a high haze value can be achieved, and a desired luminance unevenness suppressing effect can be realized with higher luminance.

  The haze value of the haze layer in the fourth embodiment is preferably 75% or more, more preferably 92% or more, still more preferably 95% or more, and particularly preferably 97% or more from the viewpoint of suppressing oblique luminance unevenness. The diffusion angle of the haze layer constituted by the resin layer having an irregular uneven pattern formed using the speckle pattern is preferably 5 degrees or more and 120 degrees or less. In order to effectively suppress oblique luminance unevenness, the haze value of the haze layer is preferably high, and the haze value increases as the diffusion angle increases. Therefore, the diffusion angle of the haze layer should be 20 degrees or more and 120 degrees or less. More preferably, it is 40 ° or more and 120 ° or less, and particularly preferably 60 ° or more and 120 ° or less.

  The non-permeable component ratio of the diffusion sheet of the fourth form is preferably 10% or more and 90% or less, more preferably 10% or more and 80% or less, and further preferably 20% or more and 80% or less. The non-transmission component ratio is preferably 90% or less from the viewpoint of suppressing a decrease in luminance, and is preferably 10% or more from the viewpoint of effectively reducing front and oblique luminance unevenness. The diffusion angle of the concavo-convex structure constituting the non-transmission component ratio adjustment pattern is preferably 0.1 degrees or more and 120 or less, more preferably 5 degrees or more and 100 degrees or less from the viewpoint of easy production. More preferably, it is 10 degrees or more and 90 degrees or less.

  The material and manufacturing method of the haze layer are the same as in the first embodiment. Further, the material and creation method of the non-transmission component ratio adjustment pattern are the same as those in the second embodiment.

  Next, with reference to FIG. 16, the structural example of the diffusion sheet of the 4th form is demonstrated. FIG. 16 is a schematic diagram illustrating a configuration example of a diffusion sheet according to a fourth embodiment.

  As shown in FIG. 16, the diffusion sheet 35 of the fourth form includes a sheet-like base material 36, a haze layer 37 provided on one main surface of the base material 36, and a uniform haze value, and a base material 36 and a non-transmission component ratio adjustment pattern 38 provided on the other main surface. Thus, in the diffusion sheet 35 according to the fourth embodiment, the haze layer 37 is provided on one main surface or the other main surface of the base material 36, and the non-transmission component ratio adjustment pattern 38 is formed on the base material 36. It is provided on the other main surface or one main surface.

  In addition, in the diffusion sheet 35 of the fourth embodiment, the irregular uneven pattern formed using the speckle pattern by interference exposure that constitutes the non-transmissive component ratio adjustment pattern 38 and the haze layer 37, regardless of the measurement direction, Both an isotropic concavo-convex pattern in which substantially the same diffusion angle is obtained and an anisotropic concavo-convex pattern having different diffusion angles depending on the measurement direction can be used. An anisotropic uneven | corrugated pattern is an uneven | corrugated pattern from which a diffusion angle differs, for example, when a diffusion angle is measured in two orthogonal directions.

Next, the manufacturing method of the diffusion sheet of the 4th form is demonstrated.
The diffusion sheet 35 shown in FIG. 16 may be manufactured by transferring the non-transmission component ratio adjustment pattern 38 to the other main surface of the substrate 36 after transferring the haze layer 37 to the one main surface of the substrate 36. The haze layer 37 may be transferred to the other main surface of the base material 36 after the non-transmission component rate adjustment pattern 38 is transferred to one main surface of the base material 36, or the non-transmission component rate adjustment pattern 38 may be transferred. The haze layer 37 may be transferred simultaneously.

[Light source unit]
Next, an example of the light source unit of this embodiment will be described.
The light source unit according to the present embodiment includes the diffusion sheet according to the embodiment and a light source. The light source unit according to the present embodiment is configured such that incident light entering the diffusion sheet from the light source is transmitted in the order of the non-transmission component adjustment rate pattern of the diffusion sheet and the haze layer.

  In order to incorporate the diffusion sheet according to the above-described embodiment into the light source unit, it is necessary to process it to a predetermined size. Although the haze layer and the non-transmission component rate adjustment pattern may be provided on the base material originally cut to a predetermined dimension, from the viewpoint of productivity, after the haze layer and the non-transmission component rate adjustment pattern are provided on the base material It is preferable to cut into predetermined dimensions.

  In the light source unit according to the present invention, it is preferable to align the diffusion sheet and the light source so that the non-transmission component ratio at a high illuminance on the light incident surface of the diffusion sheet is increased. Therefore, it is preferable that a plate for printing the non-transmission component ratio adjustment pattern is also provided with a mark for alignment at the time of cutting, and the non-transmission component ratio adjustment pattern and the mark for alignment are printed at the same time. . As a mark for alignment, a cross, a trapezoid, or a circle can be used. As a cutting means, punching with a Thomson blade is preferable because a large area can be processed, the cost is low, and the shape can be easily changed.

  Next, a configuration example of the light source unit according to the present embodiment will be described. FIGS. 17A, 17B, 18A, and 18B show schematic configurations of the light source unit according to the present embodiment. FIGS. 17A and 17B are diagrams showing an example of a light source unit using a cold cathode tube 51 (CCFL) as a line light source. FIGS. 18A and 18B show an LED 52 ( It is a figure which shows an example of the light source unit using a light emitting diode. The light source unit of the present embodiment basically includes a light source (line light source or point light source) and the diffusion sheet of the present embodiment disposed above the light source. A reflective sheet for reflecting light from the light source is preferably used below the light source.

  As shown in FIG. 17 (a), a light source unit using a line light source is arranged under three cold cathode tubes 51 arranged in parallel, and under the cold cathode tubes 51, and emits light from the cold cathode tubes 51. The reflective sheet 52 which reflects, and the diffusion sheet 53 arrange | positioned above the cold cathode tube 51 are comprised. Further, if it has the above configuration, an optical sheet, a diffusion sheet or the like may be further provided. For example, a diffusion plate (optical sheet) 54 is provided between the cold cathode tube 51 and the diffusion sheet 53. (See FIG. 17B).

  As shown in FIG. 18A, a light source unit using a point light source includes a plurality of LEDs 55 arranged in parallel, a reflection sheet 52 that is disposed below the LEDs 55, reflects light from the LEDs 55, and the LEDs 55. And a diffusion sheet 53 disposed above. Moreover, it can be set as the structure which provided the diffusion plate (optical sheet) 54 between LED55 and the diffusion sheet 53 similarly to the optical unit using a linear light source (refer FIG.18 (b)).

  In the light source unit of the present embodiment, as the light source, a linear light source such as a cold cathode tube (CCFL) 51 as shown in FIGS. 17A and 17B, or as shown in FIGS. Such LED (light emitting diode) 55 and a point light source such as a laser can be used. In this case, the light source is arranged directly below the light incident surface and the light outgoing surface of the diffusion sheet 53.

  As the reflection sheet 52, various materials can be used as long as they can reflect light. For example, a resin such as polyester or polycarbonate is foamed and fine air particles are made into a sheet, and a sheet is formed by mixing two or more resins, and resin layers with different refractive indexes are laminated. Sheet, etc. can be used. Further, the reflective sheet 52 may have an uneven shape on the surface. As these, those having inorganic fine particles added to the surface can be used as necessary.

  As the diffusing plate 54, various materials can be used as long as they can diffuse light. For example, polystyrene, acrylic resin, polycarbonate, cycloolefin polymer, or the like added with an organic polymer or inorganic fine particles having an effect of diffusing light can be used. These diffusing plates 54 have the effect of diffusing light and making the light from the lower light source uniform. Further, the diffusion plate 54 may have an uneven shape on the surface. These may be added with an organic polymer or inorganic fine particles as necessary. A diffusion plate in which two or more components are mixed and stretched to form a sheet can also be used.

  In the light source unit of the present embodiment, since the period of the non-transmission component rate distribution of the diffusion sheet 54 and the period of the illuminance distribution on the light incident surface of the diffusion sheet 54 can be made more uniform, the effect of suppressing luminance unevenness can be exhibited. ,preferable.

  Next, the non-transmission component rate in the light source unit of the present embodiment will be described with reference to FIGS. 19A and 19B are schematic perspective views of the light source unit of the present embodiment. FIG. 20 is a diagram showing the interval between the light sources and the non-transmission component rate distribution cycle in the light source unit shown in FIGS. 19 (a) and 19 (b).

  In the light source unit shown in FIG. 19A, three cold cathode fluorescent lamps (CCFLs) 51 are arranged in parallel at a predetermined light source interval S1. The longitudinal direction of each cold cathode tube 51 is arranged along the Y-axis direction. The diffusion sheet 53 is arranged in the XY plane, and the Z-axis direction orthogonal to the diffusion sheet 53 is the light exit direction. In addition, FIG.19 (b) becomes a structure which added the diffusion plate 54 to the structure of Fig.19 (a). In the diffusion sheet 53, the non-transmission component rate is periodically distributed, and the direction in which the non-transmission component rate is periodically distributed coincides with the X-axis direction orthogonal to the longitudinal direction of the cold cathode tube 51. Is arranged. The non-transmission component ratio in the surface of the diffusion sheet 53 has a peak value in the vicinity of the imaginary line L5 and a bottom value in the vicinity of the imaginary line L6.

  19A and 19B, since the period C4 of the illuminance distribution on the light incident surface of the diffusion sheet 53 is equal to the interval between the adjacent cold cathode tubes 51, the non-transmission component rate distribution period in the surface of the diffusion sheet 53. Is preferably substantially equal to the light source interval S1 of the cold cathode tube 51. In the illuminance distribution on the light incident surface of the diffusion sheet 53, when the illuminance directly above the light source is high, it is preferable to dispose a high non-transmission component ratio region of the diffusion sheet from the viewpoint of eliminating unevenness in luminance. FIG. 20 shows an example of a non-transmissive component rate distribution designed to correspond to the illuminance distribution on the light incident surface of the diffusion sheet 53.

  Further, how to change the non-transmission component ratio in the projection region (region between light sources) between the projection region (region directly above the light source) of the cold cathode tube 51 and the cold cathode tube 51 should be appropriately adjusted in order to make the luminance uniform. Can do.

  Below, the specific structural example of the light source unit of this embodiment is demonstrated. For example, the configuration shown in FIGS. 21A to 21C can be used as the configuration of the light source unit. Here, CCFL which is a linear light source is illustrated, but the light source may be a point light source such as an LED as shown in FIG. When the light source is a point light source such as an LED, the brightness of each LED is divided into two or more groups, and the LEDs belonging to those groups are regularly arranged as shown in FIGS. 23 (a) to (d), for example. It is preferable that the LEDs are arranged in a uniform manner because the brightness of the screen is uniform in the surface and the LEDs whose brightness varies during manufacturing can be used efficiently.

  In the example shown in FIG. 21A, in the configuration shown in FIG. 17B, a fine concavo-convex structure is formed on the surface between the diffusion plate 54 and the diffusion sheet 53 arranged immediately above the cold cathode tube 51. The formed surface-shaped diffusion sheet 56 is disposed, and the surface-shaped diffusion sheet 56 is disposed immediately above the diffusion sheet 53.

  In the example shown in FIG. 21B, in the configuration shown in FIG. 17B, an optical element having an arrayed prism arrangement structure above the diffusion plate 54 and the diffusion sheet 53 disposed immediately above the cold cathode tube 51. A sheet (hereinafter also referred to as “prism sheet”) 57 and a surface-shaped diffusion sheet 56 having a fine concavo-convex structure formed on the surface thereof are arranged in this order.

  In the example shown in FIG. 21C, in the configuration shown in FIG. 17B, a fine concavo-convex structure is formed on the surface above the diffusion plate 54 and the diffusion sheet 53 arranged immediately above the cold cathode tube 51. The formed surface shaping type diffusion sheet 56 and the prism sheet 57 are arranged in this order.

  Here, as the surface-shaped diffusion sheet 56, a sheet in which spherical beads of acrylic resin are coated on a sheet of polyester resin, triacetyl cellulose, polycarbonate, or the like can be used. Further, as the surface-shaped diffusion sheet 56, a sheet in which a fine uneven structure made of an ultraviolet curable resin is transferred onto a sheet of polyester resin, triacetyl cellulose, polycarbonate, or the like can be used. Such a surface-shaped diffusion sheet 56 has a function of condensing the light diffused by the diffusion plate 54 as well as the effect of diffusing and uniformizing the light. By using the surface-shaped diffusion sheet 56 and the diffusion sheet 53 in combination, luminance unevenness can be reduced, and the light source unit can be made thinner and the number of light sources can be reduced.

  As the prism sheet 57, it is possible to use an optical sheet in which prism rows having a substantially triangular shape, a substantially trapezoidal shape, and a substantially elliptical shape are arranged in an array on the surface. A shape obtained by rounding the apex of the cross-sectional shape can also be preferably used from the viewpoint of improving scratch resistance. These prism sheets 57 can be used in a form in which a prism row made of an ultraviolet curable resin is transferred onto a base material sheet such as polyester resin, triacetyl cellulose, or polycarbonate. Since such a prism sheet 57 exhibits retroreflectivity, it has a function of collecting incident light to the front. A prism apex angle of about 90 degrees is preferable because the light collecting function is exhibited well, and a prism array period of about 50 μm can reduce the occurrence of moire when a liquid crystal display device is constructed. Is preferable. By using this prism sheet 57 in combination with the diffusion sheet according to the present embodiment, it is possible to reduce luminance unevenness, reduce the thickness of the light source unit, and reduce the number of light sources.

  In the example shown in FIG. 22A, in the configuration shown in FIG. 18B, surface shaping in which a fine uneven structure is formed on the surface above the diffusion plate 54 and the diffusion sheet 53 arranged immediately above the LED 52. Two mold diffusion sheets 56 are disposed, and a reflective polarizing sheet 58 is disposed on the surface-shaped diffusion sheet 56.

  In the example shown in FIG. 22B, in the configuration shown in FIG. 18B, a prism sheet 57 is arranged above the diffusion plate 54 and the diffusion sheet 53 arranged immediately above the LED 52, and further on the prism sheet 57. A reflective polarizing sheet 58 is disposed.

  In the example shown in FIG. 22C, in the configuration shown in FIG. 18B, surface shaping in which a fine uneven structure is formed on the surface above the diffusion plate 54 and the diffusion sheet 53 arranged immediately above the LED 52. A mold diffusion sheet 56 is disposed, and a reflective polarizing sheet 58 is disposed on the surface-shaped diffusion sheet 56.

  As the reflective polarizing sheet 58, a sheet having a function of separating polarized light from natural light or polarized light can be used. As a sheet | seat which isolate | separates linearly polarized light, the film etc. which permeate | transmit one of the linearly polarized light orthogonal to an axial direction, and reflect the other are mentioned, for example. Specifically, as the reflective polarizing sheet 58, a resin having a large birefringence phase difference (polycarbonate, acrylic resin, polyester resin, etc.) and a resin having a small birefringence phase difference (cycloolefin polymer, etc.) are alternately used. A sheet obtained by multilayer lamination and uniaxial stretching, a sheet (DBEF, manufactured by 3M) having a structure in which several hundred layers of birefringent polyester resin are laminated, and the like can be used. In addition, as the configuration of the light source unit, for example, the arrangement configurations shown in FIGS. 24A to 24D, FIGS. 25A and 25B can be adopted.

  In the example shown in FIG. 24A, in the configuration shown in FIG. 17A, a diffusion plate 54 is disposed between the cold cathode tube 51 and the diffusion sheet 53, and a surface shaping type is provided immediately above the diffusion sheet 53. A diffusion sheet 56 is disposed. In the example shown in FIG. 24B, in the configuration shown in FIG. 17A, the diffusion plate 54 and the surface-shaped diffusion sheet 56 are arranged in this order above the diffusion sheet 53.

  In the example shown in FIG. 24C, in the configuration shown in FIG. 17A, a diffusion plate 54 is disposed between the cold cathode tube 51 and the diffusion sheet 53, and further, a prism sheet 57, The reflective polarizing sheets 58 are arranged in this order. Further, in the example shown in FIG. 24D, in the configuration shown in FIG. 17A, a diffusion plate 54 is disposed between the cold cathode tube 51 and the diffusion sheet 53, and a prism sheet is disposed above the diffusion sheet 53. Two prism arrangement directions of 57 are arranged orthogonally, and a surface shaping type diffusion sheet 56 is further arranged thereabove.

  In the example shown in FIG. 25A, in the configuration shown in FIG. 17A, a diffusion plate 54 is disposed between the cold cathode tube 51 and the diffusion sheet 53, and a surface shaping mold is provided above the diffusion sheet 53. The diffusion sheet 56, the prism sheet 57, and the reflective polarizing sheet 58 are arranged in this order. In the example shown in FIG. 25B, in the configuration shown in FIG. 17A, the diffusion plate 54, the surface shaping type diffusion sheet 56, the prism sheet 57, and the reflection type polarizing sheet are disposed above the diffusion sheet 53. A light source unit in which 58 is arranged in this order is shown.

[Liquid Crystal Display]
The liquid crystal display device of the present embodiment includes a predetermined display unit and the light source unit of the present embodiment described above. For example, a liquid crystal display panel having a liquid crystal layer between two polarizing plates is provided above the light source unit of this embodiment as shown in FIG.

  Next, examples carried out to clarify the effects of the present invention will be described, but the present invention is not limited to these examples.

In the following examples and comparative examples, it is difficult for the non-transmission component ratio to directly measure the transmittance at each position of 1 mm interval with respect to the x-axis direction and / or the y-axis direction of the diffusion sheet. Each sample provided with the same haze layer was printed on the substrate described in each example or comparative example on the 1 cm ² square area by printing the same printed pattern as the printed pattern of the white ink at each position. Then, a non-transmission component ratio distribution chart was created based on the non-transmission component ratio obtained from the values measured by MPC-2200. As for the diffusion angle, the angle measured by the LD8900 after entering from a surface having a fine concavo-convex structure is shown. For example, 5 ° indicates that the FWHM in any direction is 5 °. Regarding the diffusion angle distribution, FWHM was measured at 1 mm intervals with respect to the x-axis direction and / or the y-axis direction of the diffusion sheet, and a diffusion angle distribution diagram was created.

  For those not described as an optical sheet, that is, a reflective sheet, a diffuser plate, a surface-shaped diffusion sheet, a prism sheet having an arrayed prism arrangement structure, and a reflective polarizing sheet, respectively, white made of polyester resin Reflective sheet (hereinafter abbreviated as “RS”), made of polystyrene, a diffusion plate (hereinafter abbreviated as “DP”) with a thickness of 1.5 mm and a diffusing agent concentration of 13000 ppm, a hemispherical lens on a PET substrate with a thickness of 250 μm Is an optical sheet (hereinafter abbreviated as “MLF”) shaped with a UV curable resin, and a prism array with an apex angle of 90 ° and a pitch of 50 μm is shaped with a UV curable resin on a PET substrate with a thickness of 250 μm. Optical sheet (hereinafter abbreviated as “prism sheet”) and reflective polarizing sheet (hereinafter abbreviated as “DBEF”; manufactured by 3M Company) It had.

  The following three types of LEDs were used as the light source of the light source unit. The first is LW W5KM (hereinafter referred to as OSRAM-LED) manufactured by OSRAM having light distribution characteristics as shown in FIG. The second is an LED light source (hereinafter referred to as SS-LED) that has been used in the liquid crystal television UN46B8500 of SAMSUNG having light distribution characteristics as shown in FIG. The third is LM6-EWN1-03-N3 (3.5 mm square, height 2.0 mm: hereinafter referred to as “CREE-LED”) having a light distribution characteristic as shown in FIG.

  A total of 111 of these LEDs were arranged and arranged in the pattern shown in FIG. 29 to produce a light source unit. For luminance and luminance unevenness, use a Konica Minolta 2D color luminance meter (CA2000), set 70 cm away from the light source unit, and measure the average luminance value measured in the range of 120 mm x 120 mm in the center of the light source unit. It was.

  The luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction. First, an average luminance value in the x-axis direction (120 mm) is obtained, and in the y-axis direction, luminance is obtained as a standard deviation of a value obtained by dividing the luminance value at each point by the average luminance value for ± 15.2 mm from each point. I asked for unevenness. Similarly, the average luminance value in the y-axis direction (120 mm) is obtained, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ± 20.8 mm from each point in the x-axis direction. Luminance unevenness was obtained. Finally, a value obtained by averaging the standard deviation in the x-axis direction and the standard deviation in the y-axis direction (hereinafter referred to as SD) is the luminance unevenness of the light source unit. Since the LED light source is a point light source, as shown in FIG. 4B, the distribution of the diffusion angle on a line (a broken line in FIG. 4B) where the linear distance between adjacent light sources is maximum. Thought. Frontal luminance unevenness was measured from the normal direction to the screen. Oblique luminance unevenness was measured when viewed from a 45 degree direction with respect to the screen.

Here, the judgment standard of the front luminance unevenness and the oblique luminance unevenness was classified into two stages (◯, ×) as follows.
○: S. D. ≦ 0.005
X: 0.005 <S. D.

  As shown in FIG. 11A, the diffusion sheets of Examples 1 to 24 are made of a polyethylene terephthalate film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd., hereinafter referred to as “PET base material”) having a thickness of 250 μm. A white ink is printed as a light-reflective ink on one surface of the substrate 21 to form a non-transmissive component ratio adjustment pattern 23, and is formed on the other surface of the substrate using a speckle pattern by interference exposure. The haze layer 22 made of a resin layer having an irregular irregular pattern is provided. Here, for the white dot printing, a thermal transfer printing device and a white ink ribbon dedicated to the printing device (MD-5500, MDC-SCWH manufactured by Alps Electric Co., Ltd.) were used. Therefore, the dot density is constant over the entire print area.

  In the diffusion sheets of Examples 25 to 26, as shown in FIG. 11 (b), white ink is printed as light-reflective ink on one surface of the PET base material 21, and the non-transmissive component ratio adjustment pattern 23 is formed. Further, a haze layer 22 made of a resin layer having an irregular concavo-convex pattern formed using a speckle pattern by interference exposure is provided thereon. Here, for the white dot printing, a thermal transfer printing device and a white ink ribbon dedicated to the printing device (MD-5500, MDC-SCWH manufactured by Alps Electric Co., Ltd.) were used. Therefore, the dot density is constant over the entire print area.

  As shown in FIG. 15A, the diffusion sheets of Examples 27 to 28 are made of a polyethylene terephthalate film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd., hereinafter referred to as “PET substrate”) having a thickness of 250 μm. A white ink is printed as a light-reflective ink on one surface of the base material 31 to form a non-transmissive component ratio adjustment pattern 33, and a white ink made by TOKA: UV flexo white is formed on the other surface of the base material. In this configuration, PHA is uniformly applied as the haze layer 32. Here, for the white dot printing, a thermal transfer printing device and a white ink ribbon dedicated to the printing device (MD-5500, MDC-SCWH manufactured by Alps Electric Co., Ltd.) were used. Therefore, the dot density is constant over the entire print area.

  In addition, these diffusion sheets have a non-transmission component rate so that the region directly above the light source corresponds to the high non-transmission component rate region and the inter-light source region corresponds to the low non-transmission component rate region in accordance with the arrangement pattern of the LED light sources described above. An adjustment pattern is arranged, and the light source unit is formed after being cut into a predetermined size by matching the position.

Example 1
As shown in FIG. 22 (c), DP, the diffusion sheet of Example 1, MLF, and DBEF were arranged in this order above the light source to configure the light source unit of Example 1. OSRAM-LED was used as the white LED light source.

In the diffusion sheet of Example 1, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 49%. As shown in FIG. 32, the non-transmission component ratio was changed, the haze value of the haze layer was 98% and uniform in the plane, the diffusion angle was 84 degrees, the pitch of the uneven shape was 6 μm, and the height was 6 μm. . The diffusion sheet of Example 1 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 1 were calculated by the above method. The results are shown in Table 1 below.

(Example 2)
As shown in FIG. 22C, DP, the diffusion sheet of Example 2, MLF, and DBEF were arranged in this order above the light source to configure the light source unit of Example 2. OSRAM-LED was used as the white LED light source.

In the diffusion sheet of Example 2, the non-transmission component ratio in the region immediately above the light source (high non-transmission component rate region) is 50%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 47%. As shown in Fig. 32, the non-transmission component ratio is changed, the haze value of the haze layer is 98% and uniform in the plane, the diffusion angle is 80 degrees x 46 degrees, the pitch of the uneven shape is 1 μm, and the height is 1 μm. there were. The diffusion sheet of Example 2 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 2 were calculated by the above method. The results are shown in Table 1 below.

(Example 3)
As shown in FIG. 22C, DP, the diffusion sheet of Example 3, MLF, and DBEF were arranged in this order above the light source to configure the light source unit of Example 3. OSRAM-LED was used as the white LED light source.

In the diffusion sheet of Example 3, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 48%. As shown in FIG. 32, the non-transmission component ratio is changed, the haze value of the haze layer is 97%, the in-plane is uniform, the diffusion angle is 91 degrees × 29 degrees, the uneven pitch is 5 μm, and the height is 4 μm. there were. The diffusion sheet of Example 1 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 3 were calculated by the above method. The results are shown in Table 1 below.

Example 4
As shown in FIG. 22 (c), DP, the diffusion sheet of Example 4, MLF, and DBEF were arranged in this order above the light source to configure the light source unit of Example 4. OSRAM-LED was used as the white LED light source.

In the diffusion sheet of Example 4, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 49%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 46%. As shown in Fig. 32, the non-transmission component ratio is changed, the haze value of the haze layer is 96% and in-plane is uniform, the diffusion angle is 80 degrees x 1 degree, the uneven pitch is 1 μm, and the height is 2 μm. there were. The diffusion sheet of Example 4 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 4 were calculated by the above method. The results are shown in Table 1 below.

(Example 5)
As shown in FIG. 22B, the light source unit of Example 5 was configured by arranging DP, the diffusion sheet of Example 5, the prism sheet, and DBEF in this order above the light source. OSRAM-LED was used as the white LED light source.

In the diffusion sheet of Example 5, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 49%. As shown in FIG. 32, the non-transmission component ratio was changed, the haze value of the haze layer was 98% and uniform in the plane, the diffusion angle was 84 degrees, the pitch of the uneven shape was 6 μm, and the height was 6 μm. . The diffusion sheet of Example 5 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 5 were calculated by the above method. The results are shown in Table 1 below.

(Example 6)
As shown in FIG. 22B, the light source unit of Example 6 was configured by arranging DP, the diffusion sheet of Example 6, the prism sheet, and DBEF in this order above the light source. OSRAM-LED was used as the white LED light source.

In the diffusion sheet of Example 6, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 50%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 47%. As shown in Fig. 32, the non-transmission component ratio is changed, the haze value of the haze layer is 98% and uniform in the plane, the diffusion angle is 80 degrees x 46 degrees, the pitch of the uneven shape is 1 μm, and the height is 1 μm. there were. The diffusion sheet of Example 6 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 6 were calculated by the above method. The results are shown in Table 1 below.

(Example 7)
As shown in FIG. 22B, the light source unit of Example 7 was configured by arranging DP, the diffusion sheet of Example 7, the prism sheet, and DBEF in this order above the light source. OSRAM-LED was used as the white LED light source.

In the diffusion sheet of Example 7, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 48%. As shown in FIG. 32, the non-transmission component ratio is changed, the haze value of the haze layer is 97%, the in-plane is uniform, the diffusion angle is 91 degrees × 29 degrees, the uneven pitch is 5 μm, and the height is 4 μm. there were. The diffusion sheet of Example 7 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 7 were calculated by the above method. The results are shown in Table 1 below.

(Example 8)
As shown in FIG. 22B, the light source unit of Example 8 was configured by arranging DP, the diffusion sheet of Example 8, the prism sheet, and DBEF in this order above the light source. OSRAM-LED was used as the white LED light source.

In the diffusion sheet of Example 8, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 49%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 46%. As shown in Fig. 32, the non-transmission component ratio is changed, the haze value of the haze layer is 96% and in-plane is uniform, the diffusion angle is 80 degrees x 1 degree, the uneven pitch is 1 μm, and the height is 2 μm. there were. The diffusion sheet of Example 8 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 8 were calculated by the above method. The results are shown in Table 1 below.

Example 9
As shown in FIG. 22B, the light source unit of Example 9 was configured by arranging DP, the diffusion sheet of Example 9, the prism sheet, and DBEF in this order above the light source. SS-LED was used as a white LED light source.

In the diffusion sheet of Example 9, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 49%. As shown in FIG. 33, the non-transmission component ratio was changed, the haze value of the haze layer was 98%, the surface was uniform, the diffusion angle was 84 degrees, the pitch of the concavo-convex shape was 6 μm, and the height was 6 μm. . The diffusion sheet of Example 9 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 9 were calculated by the above method. The results are shown in Table 1 below.

(Example 10)
As shown in FIG. 22B, the light source unit of Example 10 was configured by arranging DP, the diffusion sheet of Example 10, the prism sheet, and DBEF in this order above the light source. SS-LED was used as a white LED light source.

In the diffusion sheet of Example 10, the non-transmission component rate in the region immediately above the light source (high non-transmission component rate region) is 47%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 43%. As shown in Fig. 33, the non-transmission component ratio is changed, the haze value of the haze layer is 88%, in-plane uniform, the diffusion angle is 58 degrees x 1 degree, the pitch of the uneven shape is 8 μm, and the height is 6 μm. there were. The diffusion sheet of Example 10 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 10 were calculated by the above method. The results are shown in Table 1 below.

(Example 11)
As shown in FIG. 22B, the light source unit of Example 11 was configured by arranging DP, the diffusion sheet of Example 11, the prism sheet, and DBEF in this order above the light source. SS-LED was used as a white LED light source.

In the diffusion sheet of Example 11, the non-transmission component ratio in the region immediately above the light source (high non-transmission component rate region) is 50%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 47%. As shown in FIG. 33, the non-transmission component ratio is changed, the haze value of the haze layer is 98% and uniform in the plane, the diffusion angle is 80 degrees x 46 degrees, the pitch of the uneven shape is 1 μm, and the height is 1 μm. there were. The diffusion sheet of Example 11 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 11 were calculated by the above method. The results are shown in Table 1 below.

(Example 12)
As shown in FIG. 22B, the light source unit of Example 12 was configured by arranging DP, the diffusion sheet of Example 12, the prism sheet, and DBEF in this order above the light source. SS-LED was used as a white LED light source.

In the diffusion sheet of Example 12, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 48%. As shown in FIG. 33, the non-transmission component ratio is changed, the haze value of the haze layer is 97%, the in-plane is uniform, the diffusion angle is 91 degrees × 29 degrees, the uneven pitch is 5 μm, and the height is 4 μm. there were. The diffusion sheet of Example 12 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 12 were calculated by the above method. The results are shown in Table 1 below.

(Example 13)
As shown in FIG. 22C, the light source unit of Example 13 was configured by arranging DP, the diffusion sheet of Example 13, MLF, and DBEF in this order above the light source. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 13, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 40%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 33%. As shown in Fig. 34, the non-transmission component ratio was changed, the haze value of the haze layer was 94%, the surface was uniform, the diffusion angle was 27 degrees, the pitch of the uneven shape was 10 µm, and the height was 2 µm. . The diffusion sheet of Example 13 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 13 were calculated by the above method. The results are shown in Table 2 below.

(Example 14)
As shown in FIG. 22 (c), DP, the diffusion sheet of Example 14, MLF, and DBEF were arranged in this order above the light source to configure the light source unit of Example 14. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 14, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 54%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 51%. As shown in FIG. 34, the non-transmission component ratio was changed, the haze value of the haze layer was 98%, the surface was uniform, the diffusion angle was 70 degrees, the pitch of the concavo-convex shape was 4 μm, and the height was 3 μm. . The diffusion sheet of Example 14 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 14 were calculated by the above method. The results are shown in Table 2 below.

(Example 15)
As shown in FIG. 22 (c), DP, the diffusion sheet of Example 15, MLF, and DBEF were arranged in this order above the light source to constitute a light source unit of Example 15. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 15, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 49%. As shown in Fig. 34, the non-transmission component ratio was changed, the haze value of the haze layer was 98%, the surface was uniform, the diffusion angle was 84 degrees, the pitch of the concavo-convex shape was 6 µm, and the height was 6 µm. . The diffusion sheet of Example 15 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 15 were calculated by the above method. The results are shown in Table 2 below.

(Example 16)
As shown in FIG. 22 (c), DP, the diffusion sheet of Example 16, MLF, and DBEF were arranged in this order above the light source to configure the light source unit of Example 16. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 16, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 48%. As shown in Fig. 34, the non-transmission component ratio is changed, the haze value of the haze layer is 97%, in-plane is uniform, the diffusion angle is 91 degrees x 29 degrees, the pitch of the uneven shape is 5 μm, and the height is 4 μm. there were. The diffusion sheet of Example 16 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 16 were calculated by the above method. The results are shown in Table 2 below.

(Example 17)
As shown in FIG. 22C, DP, the diffusion sheet of Example 17, MLF, and DBEF were arranged in this order above the light source to configure the light source unit of Example 17. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 17, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 39%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 32%. As shown in Fig. 34, the non-transmission component ratio is changed, the haze value of the haze layer is 84% and uniform in the plane, the diffusion angle is 27 degrees x 5 degrees, the pitch of the uneven shape is 9 μm, and the height is 2 μm. there were. The diffusion sheet of Example 17 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 17 were calculated by the above method. The results are shown in Table 2 below.

(Example 18)
As shown in FIG. 22B, the light source unit of Example 18 was configured by arranging DP, the diffusion sheet of Example 18, the prism sheet, and DBEF in this order above the light source. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 18, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 40%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 33%. As shown in Fig. 34, the non-transmission component ratio was changed, the haze value of the haze layer was 94%, the surface was uniform, the diffusion angle was 27 degrees, the pitch of the uneven shape was 10 µm, and the height was 2 µm. . The diffusion sheet of Example 18 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 18 were calculated by the above method. The results are shown in Table 2 below.

(Example 19)
As shown in FIG. 22B, the light source unit of Example 19 was configured by arranging DP, the diffusion sheet of Example 19, the prism sheet, and DBEF in this order above the light source. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 19, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 54%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 51%. As shown in FIG. 34, the non-transmission component ratio was changed, the haze value of the haze layer was 98%, the surface was uniform, the diffusion angle was 70 degrees, the pitch of the concavo-convex shape was 4 μm, and the height was 3 μm. . The diffusion sheet of Example 19 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 19 were calculated by the above method. The results are shown in Table 2 below.

(Example 20)
As shown in FIG. 22B, the light source unit of Example 20 was configured by arranging DP, the diffusion sheet of Example 20, the prism sheet, and DBEF in this order above the light source. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 20, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 49%. As shown in Fig. 34, the non-transmission component ratio was changed, the haze value of the haze layer was 98%, the surface was uniform, the diffusion angle was 84 degrees, the pitch of the concavo-convex shape was 6 µm, and the height was 6 µm. . The diffusion sheet of Example 20 was used such that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 20 were calculated by the above method. The results are shown in Table 2 below.

(Example 21)
As shown in FIG. 22B, the light source unit of Example 21 was configured by arranging DP, the diffusion sheet of Example 21, the prism sheet, and DBEF in this order above the light source. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 21, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 48%. As shown in Fig. 34, the non-transmission component ratio is changed, the haze value of the haze layer is 97%, in-plane is uniform, the diffusion angle is 91 degrees x 29 degrees, the pitch of the uneven shape is 5 μm, and the height is 4 μm. there were. The diffusion sheet of Example 21 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 21 were calculated by the above method. The results are shown in Table 2 below.

(Example 22)
As shown in FIG. 22B, the light source unit of Example 22 was configured by arranging DP, the diffusion sheet of Example 22, the prism sheet, and DBEF in this order above the light source. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 22, the non-transmission component ratio in the region directly above the light source (high non-transmission component rate region) is 39%, and the non-transmission component rate in the inter-light source region (low non-transmission component rate region) is 32%. As shown in Fig. 34, the non-transmission component ratio is changed, the haze value of the haze layer is 84% and uniform in the plane, the diffusion angle is 27 degrees x 5 degrees, the pitch of the uneven shape is 9 μm, and the height is 2 μm. there were. The diffusion sheet of Example 22 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 22 were calculated by the above method. The results are shown in Table 2 below.

(Example 23)
As shown in FIG. 22 (c), DP, the diffusion sheet of Example 23, MLF, and DBEF were arranged in this order above the light source to constitute a light source unit of Example 23. SS-LED was used as a white LED light source.

In the diffusion sheet of Example 23, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 49%. As shown in FIG. 32, the non-transmission component ratio was changed, the haze value of the haze layer was 98% and uniform in the plane, the diffusion angle was 84 degrees, the pitch of the uneven shape was 6 μm, and the height was 6 μm. . The diffusion sheet of Example 23 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 23 were calculated by the above method. The results are shown in Table 3 below.

(Example 24)
As shown in FIG. 22B, the light source unit of Example 24 was configured by arranging DP, the diffusion sheet of Example 24, the prism sheet, and DBEF in this order above the light source. SS-LED was used as a white LED light source.

In the diffusion sheet of Example 24, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 49%. As shown in FIG. 32, the non-transmission component ratio was changed, the haze value of the haze layer was 98% and uniform in the plane, the diffusion angle was 84 degrees, the pitch of the uneven shape was 6 μm, and the height was 6 μm. . The diffusion sheet of Example 24 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 24 were calculated by the above method. The results are shown in Table 3 below.

(Example 25)
As shown in FIG. 22C, DP, the diffusion sheet of Example 25, MLF, and DBEF were arranged in this order above the light source to constitute a light source unit of Example 25. SS-LED was used as a white LED light source.

In the diffusion sheet of Example 25, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 49%. As shown in FIG. 32, the non-transmission component ratio was changed, the haze value of the haze layer was 98% and uniform in the plane, the diffusion angle was 84 degrees, the pitch of the uneven shape was 6 μm, and the height was 6 μm. . The diffusion sheet of Example 25 was used such that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 25 were calculated by the above method. The results are shown in Table 3 below.

(Example 26)
As shown in FIG. 22B, the light source unit of Example 26 was configured by arranging DP, the diffusion sheet of Example 26, the prism sheet, and DBEF in this order above the light source. SS-LED was used as a white LED light source.

In the diffusion sheet of Example 26, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 51%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 49%. As shown in FIG. 32, the non-transmission component ratio was changed, the haze value of the haze layer was 98% and uniform in the plane, the diffusion angle was 84 degrees, the pitch of the uneven shape was 6 μm, and the height was 6 μm. . The diffusion sheet of Example 26 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 1 were calculated by the above method. The results are shown in Table 3 below.

(Example 27)
As shown in FIG. 22C, DP, the diffusion sheet of Example 27, MLF, and DBEF were arranged in this order above the light source to configure the light source unit of Example 27. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 27, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 74%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 67%. As shown in 34, the non-transmission component ratio was changed, and the haze value of the haze layer was 97%, which was uniform in the plane. The diffusion sheet of Example 27 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 18 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Example 27 were calculated by the above method. The results are shown in Table 4 below.

(Example 28)
As shown in FIG. 22C, DP, the diffusion sheet of Example 28, MLF, and DBEF were arranged in this order above the light source to constitute a light source unit of Example 28. A Cree-LED was used as the white LED light source.

In the diffusion sheet of Example 28, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 54%, and the non-transmission component rate in the region between light sources (low non-transmission component rate region) is 47%. As shown in 34, the non-transmission component ratio was changed, and the haze value of the haze layer was 77%, which was uniform in the plane. The diffusion sheet of Example 28 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 18 mm. The front luminance unevenness and the oblique luminance unevenness in the light source unit of Example 28 were calculated by the above method. The results are shown in Table 4 below.

(Comparative Example 1)
As shown in FIG. 22C, DP, the diffusion sheet of Comparative Example 1, MLF, and DBEF were arranged in this order above the light source to configure the light source unit of Comparative Example 1. OSRAM-LED was used as the white LED light source.

  As shown in FIG. 30A, the diffusion sheet of Comparative Example 1 is speckled by interference exposure on one surface of a base material 100 of a polyethylene terephthalate film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 250 μm. This is a configuration in which an impermeable component ratio adjustment pattern 101 made of a resin layer having an irregular concavo-convex pattern formed using a pattern is provided. As shown in FIG. 35, the non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 43%, the diffusion angle is 74 degrees, the non-transmission component rate in the inter-light source region is 21%, and the diffusion angle is 19. The diffusion angle has changed. The diffusion sheet of Comparative Example 1 was used so that the non-transmissive component ratio adjustment pattern side was the light exit surface.

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Comparative Example 1 were calculated by the above method. The results are shown in Table 1 below.

(Comparative Example 2)
As shown in FIG. 22B, DP, the diffusion sheet of Comparative Example 2, MLF, and DBEF were arranged in this order above the light source to constitute a light source unit of Comparative Example 2. OSRAM-LED was used as the white LED light source.

  As shown in FIG. 30A, the diffusion sheet of Comparative Example 2 is speckled by interference exposure on one surface of a base material 100 of a polyethylene terephthalate film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 250 μm. This is a configuration in which an impermeable component ratio adjustment pattern 101 made of a resin layer having an irregular concavo-convex pattern formed using a pattern is provided. The non-transmission component rate in the region immediately above the light source is 43% and the diffusion angle is 74 degrees, the non-transmission component rate in the region between the light sources is 21%, the diffusion angle is 19 degrees, and the diffusion angle changes as shown in FIG. Yes. The diffusion sheet of Comparative Example 2 was used so that the non-transmission component ratio adjustment pattern side was the light exit surface.

  Here, the distance h between the light incident surface of RS and DP was set to 9.5 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Comparative Example 2 were calculated by the above method. The results are shown in Table 1 below.

(Comparative Example 3)
As shown in FIG. 22 (c), DP, the diffusion sheet of Comparative Example 3, MLF, and DBEF were arranged in this order above the light source to constitute a light source unit of Comparative Example 3. A Cree-LED was used as the white LED light source.

As shown in FIG. 30 (b), the diffusion sheet of Comparative Example 3 has a light-reflective ink on one surface of a base material 100 of a polyethylene terephthalate film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 250 μm. In this configuration, white ink is printed and the non-transmissive component ratio adjustment pattern 102 is formed. Here, for the white dot printing, a thermal transfer printing device and a white ink ribbon dedicated to the printing device (MD-5500, MDC-SCWH manufactured by Alps Electric Co., Ltd.) were used. Therefore, the dot density is constant over the entire print area. The non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 35%, and the non-transmission component rate in the inter-light source region (low non-transmission component rate region) is 28%. The rate is changing. The diffusion sheet of Comparative Example 3 was used so that the base material side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Comparative Example 3 were calculated by the above method. The results are shown in Table 2 below.

(Comparative Example 4)
As shown in FIG. 22B, DP, the diffusion sheet of Comparative Example 4, MLF, and DBEF were arranged in this order above the light source to constitute a light source unit of Comparative Example 4. A Cree-LED was used as the white LED light source.

As shown in FIG. 30 (b), the diffusion sheet of Comparative Example 4 is a light-reflective ink on one surface of a base material 100 of a polyethylene terephthalate film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 250 μm. In this configuration, white ink is printed and the non-transmissive component ratio adjustment pattern 102 is formed. Here, for the white dot printing, a thermal transfer printing device and a white ink ribbon dedicated to the printing device (MD-5500, MDC-SCWH manufactured by Alps Electric Co., Ltd.) were used. Therefore, the dot density is constant over the entire print area. The non-transmission component rate in the region directly above the light source (high non-transmission component rate region) is 35%, and the non-transmission component rate in the inter-light source region (low non-transmission component rate region) is 28%. The rate is changing. The diffusion sheet of Comparative Example 4 was used so that the base material side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 20 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Comparative Example 4 were calculated by the above method. The results are shown in Table 2 below.

(Comparative Example 5)
As shown in FIG. 22C, DP, the diffusion sheet of Comparative Example 5, MLF, and DBEF were arranged in this order above the light source to constitute a light source unit of Comparative Example 5. A Cree-LED was used as the white LED light source.

  As shown in FIG. 30C, the diffusion sheet of Comparative Example 5 is a light-reflective ink on one main surface of a substrate 100 of a polyethylene terephthalate film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 250 μm. As a haze layer 103, a white ink made by TOKA: UV flexo white PHA is uniformly applied as the haze layer 103 on the other surface of the substrate. is there. Here, for the white dot printing, a thermal transfer printing device and a white ink ribbon dedicated to the printing device (MD-5500, MDC-SCWH manufactured by Alps Electric Co., Ltd.) were used. Therefore, the dot density is constant over the entire print area.

The diffusion sheet of Comparative Example 5 has a non-transmission component rate of 45% in the region directly above the light source (high non-transmission component rate region) and a non-transmission component rate in the region between light sources (low non-transmission component rate region) of 38%. As shown in 34, the non-transmission component ratio was changed, and the haze value of the haze layer was 14%, which was uniform in the plane. The diffusion sheet of Comparative Example 5 was used so that the haze layer side was the light exit surface. At this time, the pitch between white dots in the high non-transmission component ratio region was 283 μm, one dot was 198 μm in diameter, and an area of 13619 μm ² , and the dot density per unit area was 35%. The unit area was 216 μm × 182 μm = 39312 μm ² . The pitch between white dots in the low non-transmissive component ratio region was 283 μm, one dot was an ellipse having a diameter of 158 μm and an area of 8545 μm ² , and the dot density per unit area was 22%. The unit area was 216 μm × 182 μm = 39312 μm ² .

  Here, the distance h between the light incident surface of RS and DP was 18 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Comparative Example 5 were calculated by the above method. The results are shown in Table 4 below.

(Comparative Example 6)
As shown in FIG. 22C, DP, the diffusion sheet of Comparative Example 6, MLF, and DBEF were arranged in this order above the light source to constitute a light source unit of Comparative Example 6. A Cree-LED was used as the white LED light source.

  As shown in FIG. 30 (d), the diffusion sheet of Comparative Example 6 is formed as a haze layer 102 on one surface of a base material 100 of a polyethylene terephthalate film (Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 250 μm. A white ink manufactured by TOKA Co., Ltd .: UV flexo white PHA is uniformly applied.

  In the diffusion sheet of Comparative Example 6, the non-transmission component rate was uniform in the plane, and the haze value of the haze layer was 97% and uniform in the plane. The diffusion sheet of Comparative Example 6 was used so that the haze layer side was the light exit surface.

  Here, the distance h between the light incident surface of RS and DP was 18 mm. Front luminance unevenness and oblique luminance unevenness in the light source unit of Comparative Example 6 were calculated by the above method. The results are shown in Table 4 below.

(Table 1)

(Table 2)

(Table 3)

(Table 4)

  The present invention has an effect that uneven brightness unevenness and oblique brightness unevenness can be reduced, and can be suitably used particularly as a diffusion sheet and a light source unit for a liquid crystal display device.

1, 20, 25, 30, 35, 53 Diffusion sheet 11, 21, 26, 31, 36, 100 Base material 12, 22, 27, 32, 37, 103 Haze layer 13, 23, 28, 33, 38, 101 , 102 Non-transmission component ratio adjustment pattern 14, 51 Cold cathode tube 15, 55 LED
52 Reflective Sheet 54 Diffuser Plate 56 Surface-Shaped Diffusion Sheet 57 Prism Sheet 58 Reflective Polarizing Sheet

Claims (22)

  A sheet-like base material, a haze layer provided on one main surface of the base material, and a non-permeable component rate adjustment pattern provided on one main surface or the other main surface of the base material, A diffusion sheet, wherein the haze value of the haze layer is uniform in the sheet plane and in the range of 75% to 100%, and the non-transmission component ratio is non-uniform in the sheet plane.   The diffusion sheet according to claim 1, wherein the haze layer is a resin layer having an irregular concavo-convex pattern formed using a speckle pattern formed by interference exposure.   The diffusion sheet according to claim 2, wherein a diffusion angle of the haze layer is 5 degrees to 120 degrees.   The diffusion sheet according to claim 1, wherein the haze layer contains a light-reflecting ink cured product containing a light diffusing agent.   5. The resin layer according to claim 1, wherein the non-transmissive component ratio adjustment pattern is a resin layer having an irregular concavo-convex pattern formed using a speckle pattern formed by interference exposure. Diffusion sheet.   The diffusion sheet according to claim 5, wherein a diffusion angle of the non-transmissive component ratio adjustment pattern is 0.1 to 120 degrees.   The diffusion sheet according to any one of claims 1 to 4, wherein the non-transmission component rate adjustment pattern contains a light-reflecting ink cured product containing a light diffusing agent. The diffusion sheet according to claim 7, wherein the non-transmission component ratio adjustment pattern is composed of discontinuous dots, and an area of each dot is in a range of 25 to 250,000 μm ² .   The said haze layer is provided on one main surface of the said base material, The said non-permeable component rate adjustment pattern is provided on the other main surface of the said base material, The Claim 1 characterized by the above-mentioned. Item 9. The diffusion sheet according to any one of Items 8.   9. The non-transmission component ratio adjustment pattern is provided on one main surface of the base material, and the haze layer is provided on the non-transmission component ratio adjustment pattern. A diffusion sheet according to any one of the above.   In the non-transmission component ratio distribution diagram in which the horizontal axis represents the relative position within the sheet surface in a predetermined direction and the vertical axis represents the non-transmission component ratio at the relative position within the sheet surface, the peak of the non-transmission component ratio 11. The diffusion sheet according to claim 1, wherein there are a plurality of peak points indicating a value and a plurality of bottom points indicating a bottom value of the non-transmissive component ratio.   The diffusion sheet according to claim 11, wherein the diffusion sheet has a peak point of the non-transmissive component ratio and a bottom point of the non-transmissive component ratio alternately and periodically.   A light source unit comprising the diffusion sheet according to any one of claims 1 to 12 and a light source, wherein the diffusion sheet is configured such that incident light from the light source is the non-transmissive component rate adjustment pattern, A light source unit, wherein the light source units are arranged so as to pass through in the order of the haze layers.   The light source unit according to claim 13, comprising at least two of the light sources.   The light source unit according to claim 13 or 14, wherein the light source is a linear light source.   The light source unit according to claim 13 or 14, wherein the light source is a point light source.   The light source according to any one of claims 13 to 16, wherein a period of the non-transmission component ratio adjustment pattern of the diffusion sheet is substantially equal to a period of the illuminance distribution on the light incident surface of the diffusion sheet. unit.   The diffusing plate, which is disposed between the diffusing sheet and the light source and contains a diffusing agent therein, and a reflecting sheet disposed below the light source, are provided. The light source unit according to any one of the above.   The light source unit according to any one of claims 13 to 18, further comprising a lens sheet disposed above the diffusion sheet.   The light source unit according to any one of claims 13 to 19, further comprising a prism sheet disposed above the diffusion sheet.   The light source unit according to claim 13, further comprising a reflective polarizing sheet disposed above the diffusion sheet.   A liquid crystal display device comprising: a liquid crystal display panel; and the light source unit according to claim 13 for supplying light to the liquid crystal display panel.

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