WO2010050522A1 - Optical sheet, optical sheet manufacturing method, light source including optical sheet, and display device - Google Patents

Optical sheet, optical sheet manufacturing method, light source including optical sheet, and display device Download PDF

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Publication number
WO2010050522A1
WO2010050522A1 PCT/JP2009/068522 JP2009068522W WO2010050522A1 WO 2010050522 A1 WO2010050522 A1 WO 2010050522A1 JP 2009068522 W JP2009068522 W JP 2009068522W WO 2010050522 A1 WO2010050522 A1 WO 2010050522A1
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WO
WIPO (PCT)
Prior art keywords
optical sheet
shape
lens
unit lens
line
Prior art date
Application number
PCT/JP2009/068522
Other languages
French (fr)
Japanese (ja)
Inventor
大資 今井
祐輝 三吉
敏夫 淡路
Original Assignee
株式会社日本触媒
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Publication date
Application filed by 株式会社日本触媒 filed Critical 株式会社日本触媒
Priority to CN2009801432461A priority Critical patent/CN102197324A/en
Publication of WO2010050522A1 publication Critical patent/WO2010050522A1/en

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0012—Arrays characterised by the manufacturing method
    • G02B3/0031—Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0268—Diffusing elements; Afocal elements characterized by the fabrication or manufacturing method
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/0074—Production of other optical elements not provided for in B29D11/00009- B29D11/0073
    • B29D11/00788—Producing optical films
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0037—Arrays characterized by the distribution or form of lenses
    • G02B3/0043—Inhomogeneous or irregular arrays, e.g. varying shape, size, height
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G02F1/133607—Direct backlight including a specially adapted diffusing, scattering or light controlling members the light controlling member including light directing or refracting elements, e.g. prisms or lenses

Definitions

  • the present invention relates to an optical sheet, a method for manufacturing the optical sheet, a light source device including the optical sheet, and a display device.
  • the light source of the liquid crystal display device includes an edge light type and a direct type, but a large type liquid crystal display device generally uses a direct type light source in which a plurality of cold cathode tubes are arranged as the light source.
  • the portion where the cold-cathode tube is present is bright, while the portion where the cold-cathode tube is not present is relatively dark, resulting in uneven brightness. There is a problem of being reflected in. Therefore, by arranging various optical sheets between the cold cathode fluorescent lamp and the liquid crystal panel, light emitted from the cold cathode fluorescent lamp is uniformly diffused over the entire screen.
  • Liquid crystal display devices are required to be further thinned. For this reason, the distance between the cold cathode fluorescent lamp and the screen has to be narrowed, and it has become difficult to sufficiently diffuse the light from the cold cathode fluorescent lamp. . Further, in order to reduce the cost, the number of cold cathode tubes is also reduced, and it is difficult to uniformly diffuse light from the cold cathode tubes as the interval between the cold cathode tubes is increased. Therefore, under such severe conditions, as a method of eliminating luminance unevenness and improving luminance, select an optical sheet with a lens as the optical sheet placed closest to the light source and adjust the lens shape. Has been done.
  • At least one prism sheet is selected as the second and subsequent optical sheets with respect to the direction from the light source to the liquid crystal panel.
  • a plurality of prism lenses having a triangular cross section are arranged in parallel.
  • a prism sheet or a lenticular lens sheet in which a plurality of cylindrical lenses having a cylindrical convex surface are arranged in parallel is used as an alternative to a conventional optical sheet.
  • Prism sheets and lenticular lens sheets can prevent the amount of transmitted light from decreasing and the brightness in the viewing angle direction because the number of incident rays repeats catadioptric refraction is less than optical sheets with conventional light diffusing agents. Can be improved.
  • the prism sheet can improve the luminance, there is a limit to the uniform distribution thereof.
  • the lenticular lens sheet can also increase the uniformity of the luminance distribution as compared with the prism sheet, it is difficult to completely eliminate the luminance unevenness under the severe cold cathode tube installation conditions as described above.
  • An optical sheet having lenses arranged in a straight bowl on the light exit surface is arranged at a position closest to the light source, and at least one prism is provided on the optical sheet arranged second or later in the direction from the light source to the liquid crystal panel.
  • the light diffusibility is enhanced by the effect of the prism, and the front luminance can be increased. Therefore, it is considered to be an optical sheet configuration for a light source that is optimal for thinning a liquid crystal television and reducing the number of cold cathode tubes.
  • An object of the present invention is to reduce luminance unevenness at an intermediate point between line light sources (for example, cold-cathode tubes) arranged in parallel with each other and directly above the line light source, and to be arranged second or later in the direction from the light source to the liquid crystal panel. It is to provide an optical sheet capable of obtaining a uniform luminance distribution by combination with the optical sheet, a manufacturing method of the optical sheet, a light source device including them, and a liquid crystal display device.
  • line light sources for example, cold-cathode tubes
  • the inventors have obtained a cross section perpendicular to the length direction of the lens group in the lens group formed in a linear bowl shape on the surface of the optical sheet.
  • the outer peripheral line of the convex part of all the lenses in the shape is composed of a curve and / or a straight line, and the tangent line of the curve and / or the angle formed by the straight line and the base line adjusts the ratio of the part within a specific range.
  • the optical sheet of the present invention is an optical sheet having a convex lens group formed on the surface in the form of a straight bowl, and the convex parts of all the lenses in a cross-sectional shape perpendicular to the length direction of the lens group.
  • a portion (X 1 ) in which the outer peripheral line is composed of a curve and / or a straight line and the angle ( ⁇ ) between the tangent and / or the straight line and the base line at all points on the curve is ⁇ ⁇ 40 °
  • a portion (X 2 ) where an angle ( ⁇ ) formed between a tangent at all points on the curve and / or the straight line and a base line is 25 ° ⁇ ⁇ ⁇ 35 °
  • the total length (x 1total ) of the length (x 1 ) projected on the base line of the lens group is 25% or more and 60% or less of the total length (P total ) of the base line length of the lens group
  • said portion (X 2) the lens group length projected in baseline of (x 2 Total (x 2total), characterized in that the total length of the lens group of the base line is 60% or less 25% or more (P total).
  • the lens group is configured such that the convex outer peripheral line in the vertical cross-sectional shape with respect to the length direction of the unit lens is mainly composed of a curve, and tangents at all points on the curve and the angle of the baseline (theta 11) is the theta 11 ⁇ 40 ° curved section and (R 11), the tangent angle of the base line at all points on the curve (theta 12) is 25 ° ⁇ theta
  • the ratio of the total length (r 11 ) of the curved portion (R 11 ) projected onto the base line of the unit lens shape to the total length of the base line includes the curved portion (R 12 ) satisfying 12 ⁇ 35 °.
  • the ratio of the total length (r 12 ) of the curved portion (R 12 ) projected onto the base line of the unit lens shape to the total length of the base line is 25% or more and 60% or less.
  • % Is an optical sheet having a first unit lens (see FIG. 6) that is less than or equal to%.
  • the lens group is formed of a shape in which the convex portion outer peripheral line in the vertical cross-sectional shape with respect to the length direction of the unit lens is formed by connecting two or more curves and one or more straight lines.
  • the curves include a curve portion (R 21 ) in which an angle ( ⁇ 21 ) between a tangent line and a base line at all points on the curve is ⁇ 21 ⁇ 40 °, and the straight line (R 22 ) and a base line ( ⁇ 22 ) is an optical sheet having a second unit lens (see FIGS. 7 to 10) in which 25 ° ⁇ ⁇ 22 ⁇ 35 °.
  • the lens group includes a unit lens (see FIG. 12) having the following shape 1 and a unit lens having the shape 2 as a convex portion outer peripheral line having a vertical cross-sectional shape with respect to the length direction. It is an optical sheet having (see FIG. 13).
  • ⁇ Shape 1 ⁇ A portion in which an outer peripheral line is a curve or a straight line, and an angle ( ⁇ 32 ) between a tangent or a straight line at all points on the curve and a base line of the unit lens cross-sectional shape is 25 ° ⁇ ⁇ 32 ⁇ 35 ° (R 32 ), and the total length (r 32 ) of the portion (R 32 ) projected onto the base line of the unit lens cross-sectional shape is 90% or more with respect to the total base line length of the unit lens cross-sectional shape A shape characterized by ⁇ Shape 2 ⁇
  • the total length (r 33 ) projected on the base line of the unit lens shape of the portion (R 33 ) whose outer peripheral line is mainly composed of a curved portion and is represented by a single quadratic curve,
  • the angle ( ⁇ 31 ) between the tangent line and the base line at all points on the curve is 90% or more with respect to the total length of the base line of the unit lens shape and is a part of the portion
  • the ratio (r 31 ) of the total length (r 31 ) projected to the base line of the lens cross-sectional shape of the part (R 31 ) is 20% or more including the curved line part (R 31 ) where 31 ⁇ 40 °
  • the present invention also includes a method for manufacturing the optical sheet, a light source device for a display device that requires the optical sheet and a prism sheet, and a display device that includes the light source device for the display device.
  • the luminance in the viewing angle direction in the region immediately above the line light source of the light source device and the luminance in the viewing angle direction in the intermediate region of the adjacent line light sources can be independently adjusted. It becomes possible. Therefore, in various apparatus settings (apparatus configuration, light source apparatus conditions, combinations with optical sheets other than the present invention), high brightness uniformity on the light exit surface side in the settings can be realized.
  • FIG. 7 is an explanatory diagram of a surface shape of a first unit lens in Examples 1 to 6.
  • FIG. 10 is an explanatory diagram of a surface shape of a first unit lens in Example 7.
  • FIG. 10 is an explanatory diagram of a surface shape of a first unit lens in Example 8.
  • FIG. 14 is an explanatory diagram of a surface shape of a first unit lens in Example 9.
  • FIG. 14 is an explanatory diagram of a first unit lens surface shape in Example 10.
  • FIG. 12 is an explanatory diagram of a surface shape of a first unit lens in Example 11. It is explanatory drawing of an example of the 1st unit lens surface shape in Examples 12 and 13.
  • FIG. FIG. 22 is an explanatory diagram of a lens group of the optical sheet of Example 14.
  • 10 is an explanatory diagram of a lens group of an optical sheet of Comparative Example 5.
  • FIG. 10 is an explanatory diagram of a lens group of an optical sheet of Comparative Example 5.
  • FIG. 42 is an explanatory diagram of a lens group of an optical sheet according to Example 27.
  • FIG. FIG. 22 is an explanatory diagram of an example of a unit lens cross-sectional shape 1 in Examples 28 to 33.
  • FIG. 22 is an explanatory diagram of an example of a unit lens cross-sectional shape 2 in Examples 28 to 35. It is explanatory drawing of an example of the unit lens cross-sectional shape 1 in Example 34,35.
  • FIG. 42 is an explanatory diagram of a lens group of an optical sheet according to Examples 28 to 33. It is explanatory drawing of arrangement
  • the first optical sheet refers to an optical sheet arranged first in the direction from the light source to the liquid crystal panel
  • the second and subsequent optical sheets are the second, third, and fourth, respectively.
  • the optical sheets in the order of arrangement see FIG. 1.
  • the optical sheet closest to the front panel corresponds to the fourth optical sheet denoted by reference numeral 6 in FIG. If these optical sheets can achieve the purpose of installation (for example, improvement in luminance) without causing any hindrance (for example, significant increase in thickness and cost), there is no upper limit on the number of sheets.
  • the optical sheet of the present invention is an optical sheet having a convex lens group formed on the surface in a linear bowl shape, all in a vertical cross-sectional shape with respect to the length direction of the lens group.
  • the outer peripheral line of the convex portion of the lens is composed of a curve and / or a straight line, and the tangent and / or the angle ( ⁇ ) between the straight line and the base line at all points on the curve is ⁇ ⁇ 40 °.
  • an element (X 1) includes a portion (X 2) the angle of the tangent line and / or the straight line and the baseline (theta) is 25 ° ⁇ ⁇ ⁇ 35 ° at all points on the curve
  • the total length (x 1total ) of the length (x 1 ) projected onto the base line of the lens group of the portion (X 1 ) is 25% or more and 60% of the total length (P total ) of the base line length of the lens group. less and, and, on the baseline of the lens group of the partial (X 2)
  • the length and shadow (x 2) total (x 2total) characterized in that the total length of the lens group of the base line is 60% or less 25% or more (P total).
  • the light from the light source can be sufficiently diffused into the intermediate portion of the cold cathode tube array, and the luminance in the viewing angle direction at the intermediate portion can be increased. Can be improved. Furthermore, in order to increase the luminance in the viewing angle direction, the luminance of the upper region of the cold cathode tube is also increased when an optical sheet such as a commonly used prism sheet or a diffusion sheet with a lens is superimposed on the optical sheet of the present invention. Can be secured sufficiently.
  • the straight line as used in the field of this invention means the straight line segment which connects the terminal ends
  • the curve in which the line segment which connects a terminal part has a very small curvature near a straight line is also contained.
  • the curve referred to in the present invention includes a curve that is different from a straight line but has a small curvature close to the straight line.
  • the minimum structural unit defined in the present invention is in the order of microns, but when observed in the order of microns, for example, when a vertical section of an optical sheet is observed with an electron microscope, the curved portion defined in the present invention is In the case of a curve with a small curvature that is difficult to determine as a curve in that order, the determination is performed as follows, for example.
  • the value of 100 ⁇ d / A exceeds 1 when the shortest distance d between the point on the curve farthest from the straight line and the straight line In this case, it is determined as a curve, and when the value of 100 ⁇ d / A is 1 or less, it is determined as a straight line.
  • the lowest part is the lowest point of the outer peripheral line of the convex part of the unit lens.
  • the base line is a straight line connecting the lowest part and the lowest part.
  • the top portion is the highest point from the base line in the outer peripheral line of the convex portion of the unit lens.
  • an angle ( ⁇ ) formed between a tangent line at all points on the curve and / or the straight line and a base line is ⁇ ⁇ 40 °.
  • Examples of the portion (X 1 ) include a curved portion (R 11 ) of the first unit lens, a curved portion (R 21 ) of the second unit lens, and a curved portion (R 31 ) of the unit lens having the shape 2 described later. Is applicable.
  • the length (x 1 ) for example, the total length (r 11 ) obtained by projecting the portion (X 1 ) of the first unit lens, which will be described later, onto the base line, and the portion of the second unit lens ( X 1) total length of the projected to the ground line (r 21), total of said portion (X 1) a length obtained by projecting the baseline of the unit lens having the shape 2 (r 31) corresponds.
  • an angle ( ⁇ ) formed between a tangent line at all points on the curve and / or the straight line and a base line is 25 ° ⁇ ⁇ ⁇ 35 °.
  • Examples of the portion (X 2 ) include a curved portion (R 12 ) of the first unit lens described later, a straight portion (R 22 ) of the second unit lens, a portion of the unit lens (R 32 ) having the shape 1, The unit lens portion (R 34 ) having the shape 2 is applicable.
  • the length (x 2 ) for example, the total length (r 12 ) obtained by projecting the portion (X 2 ) of the first unit lens, which will be described later, onto the base line
  • the length projected on the base line of the lens group is obtained for the part (X 1 ) and the part (X 2 ) of all the lenses of the convex lens group formed on the surface.
  • the total (x 1total ) and the total (x 2total ) include not only a first unit lens, a second unit lens, a unit lens having shape 1 and a unit lens having shape 2 which will be described later, but also other structures.
  • unit lenses having a lenticular shape eg, lenticular shape. That is, in the second embodiment to be described later, as shown in FIG. 2, the total of the second unit lens and the lenticular unit lens is obtained.
  • these surface shapes are set on the light exit surface side.
  • the surface shape configuration on the light incident surface side of the optical sheet of the present invention is not particularly limited and can be appropriately selected from flat surfaces, embossed surfaces, mat surfaces, surfaces having optical elements such as lenses, etc.
  • An embossed surface and a mat surface are preferably used from the viewpoints of preventing sticking, preventing sound noise, and exhibiting a light scattering effect.
  • the lens group includes a first unit lens (see FIG. 6).
  • the lens group includes a second unit lens (see FIGS. 7 to 10).
  • a convex portion outer peripheral line in a vertical cross-sectional shape with respect to the length direction of the unit lens is mainly composed of a curve, and tangent lines and base lines of all points on the curve are formed.
  • angle (theta 11) is the theta 11 ⁇ 40 ° curved section and (R 11), the angle between the tangent and the base line at all points on the curve (theta 12) is 25 ° ⁇ ⁇ 12 ⁇ 35 ° curved portion is comprises (R 12), wherein the curved portion (R 11) said unit said fraction of the total length of the base line of the lens total length of the projected the baseline configuration (r 11) is 25% or more 60 % And the ratio of the total length (r 12 ) of the curved portion (R 12 ) projected onto the base line of the unit lens shape to the total length of the base line is 25% or more and 60% or less. .
  • the ratio of the total length (r 11 ) projected onto the base line of the curved portion (R 11 ) to the total length of the base line is 25% or more and 60% or less, and is projected onto the base line of the curved portion (R 12 ).
  • the luminance of the upper region of the cold cathode tube is also increased when an optical sheet such as a commonly used prism sheet or a diffusion sheet with a lens is superimposed on the optical sheet of the present invention. Can be secured sufficiently. Therefore, by using the optical sheet of the first embodiment, the distance between the line light source and the optical sheet due to further thinning, the number of line light sources for reducing the energy consumption and cost of the liquid crystal display device It has become possible to eliminate uneven brightness even in liquid crystal display panels, where it has become increasingly difficult to eliminate uneven brightness, which is an increase in the interval between line light sources due to the reduction in the number of lines.
  • Curve part The curve part (R 11 ) is preferably a part of a quadratic curve from the viewpoints of design easiness, workability, and optical performance. Further, the curved portion (R 11 ) may be a combination of one or two or more quadratic curves, and may be arranged symmetrically on the right and left of the convex portion outer peripheral line or asymmetrically arranged.
  • the quadratic curve means an ellipse including a circle, a hyperbola, and a parabola.
  • the eccentricity is preferably 0.50 or more and 0.95 or less, more preferably 0.70 or more and 0.93 or less, and 0.80 or more and 0.8. 90 or less is more preferable.
  • the curved part (R 12 ) may be a part of a quadratic curve, like the curved part (R 11 ).
  • the curve portion (R 12 ) has a narrow tangent angle of 25 ° ⁇ ⁇ 12 ⁇ 35 ° ( ⁇ 12 ) between the tangent line and the base line at all points on the curve, and the base line. Since the ratio of the total projected length (r 12 ) to the total length of the base line needs to be 25% or more and 60% or less, it is not necessarily a part of the quadratic curve. It may be composed of any one or more curves that satisfy the following conditions.
  • be arranged symmetrically to the right and left of the convex portion outer peripheral line may be arranged asymmetrically.
  • the curve on the outer periphery of the convex portion in the vertical cross-sectional shape with respect to the length direction of the first unit lens is composed of two or more types of segments including the curved portion (R 11 ) and the curved portion (R 12 ).
  • the ratio of the total length (r 11 ) projected onto the base line of the curved portion (R 11 ) to the total length of the base line is 25% or more and 60% or less.
  • the ratio of the total (r 11 ) exceeds 60%, a cold cathode is formed when an optical sheet such as a prism sheet or a diffusion sheet with a lens generally used for increasing the luminance in the viewing angle direction is overlaid.
  • the brightness of the tube upper area is lowered, causing new brightness unevenness.
  • the ratio of the total (r 11 ) is more preferably 27% or more and 58% or less, and further preferably 30% or more and 55% or less.
  • the ratio of the total length (r 12 ) projected onto the base line of the curved portion (R 12 ) to the total length of the base line is 25% or more and 60% or less.
  • the ratio of the total (r 12 ) is less than 25%, in order to increase the luminance in the viewing angle direction, when a commonly used optical sheet such as a prism sheet or a diffusion sheet with a lens is superposed, a cold cathode The luminance of the tube upper area is lowered, and it becomes difficult to eliminate luminance unevenness.
  • the ratio of the total (r 12 ) is more preferably 27% or more and 58% or less, and further preferably 30% or more and 55% or less.
  • curved portions may be directly connected to form a convex portion outer peripheral line, or an angle formed by a tangent and a base line at a straight line portion or a point on the curve.
  • ( ⁇ 13 ) may be connected via a curved portion (R 13 ) of 35 ° ⁇ 13 ⁇ 40 ° or ⁇ 13 ⁇ 25 °.
  • the ratio of the total length (r 13 ) projected onto the base line of these joints to the total base line length is preferably 40% or less. 20% or less is more preferable.
  • the connecting method of the curved portion (R 11 ) and the curved portion (R 12 ) may be symmetrical with respect to the outer peripheral line of the convex portion or may be asymmetrical with the left and right sides, and these connecting methods are adjusted. By doing so, it is possible to eliminate more uneven brightness.
  • the number of the curved portion (R 11 ) and the curved portion (R 12 ) is not particularly limited as long as the ratio of r 11 and r 12 is satisfied, but it is preferable that two exist each. Either of the setting positions of the curved portion (R 11 ) and the curved portion (R 12 ) may be close to the base portion. It is desirable from the viewpoint of moldability that the curved portion (R 11 ) is close to the base portion.
  • the curved portion (R 11 ) is close to the base portion, and the curved portion (R 11 ) and the curved portion (R 12 ) are symmetric with respect to the center line of the unit lens. .
  • the second unit lens is formed of a shape in which a convex outer peripheral line in a vertical cross-sectional shape with respect to the length direction of the unit lens is formed by connecting two or more curves and one or more straight lines, and At least two of the curves include a curved portion (R 21 ) in which an angle ( ⁇ 21 ) between a tangent line and a base line at all points on the curve is ⁇ 21 ⁇ 40 °, and the straight line (R 22 ) and the base The angle ( ⁇ 22 ) between the lines is 25 ° ⁇ ⁇ 22 ⁇ 35 °.
  • the straight line of the outer periphery of the convex portion in the vertical section, the number of curves, the position, ⁇ 21 of the curve, ⁇ 22 of the straight line, the luminance in the viewing angle direction in the region immediately above the cold cathode tube of the light source device, It is possible to independently adjust the luminance in the viewing angle direction in the intermediate region between adjacent cold-cathode tubes. Therefore, high brightness uniformity of the entire surface of the light source device can be realized in various device settings (light source device conditions, combinations with optical sheets other than the present invention).
  • the two or more curves and the one or more straight lines are, for example, a unit lens structure having a convex portion outer peripheral line having a cross section as shown in FIGS.
  • the number of straight lines is preferably two or more from the viewpoints of easy manufacture of a matrix used for lens shaping, ease of adjustment of optical performance as the entire optical sheet, and the like.
  • the curve constituting the convex outer peripheral line of the second unit lens is preferably a part of a quadratic curve such as an ellipse (including a circle) from the viewpoint of ease of design, workability, and optical performance. It may be a combination of one or more quadratic curves.
  • the eccentricity is preferably 0.50 or more and 0.95 or less. 70 or more and 0.93 or less are more preferable, and 0.80 or more and 0.90 or less are more preferable.
  • the angle ( ⁇ 21 ) between the tangent line and the base line at all points on the curve is ⁇ 21 ⁇ 40 °.
  • the ratio of the total length (r 21 ) projected on the base line of the curved portion (R 21 ) to the total length of the base line is preferably 25% or more and 60% or less. If the ratio of the total (r 21 ) is less than 25%, the light diffusion to the intermediate portion of the cold cathode tube array is reduced, and the luminance in the viewing angle direction at the intermediate portion is reduced, making it difficult to eliminate luminance unevenness. Become.
  • the ratio of the total (r 21 ) exceeds 60%, a cold cathode is formed when an optical sheet such as a prism sheet or a diffusion sheet with a lens generally used for increasing the luminance in the viewing angle direction is overlaid.
  • the brightness of the tube upper area is lowered, causing new brightness unevenness.
  • the ratio of the total (r 21 ) is more preferably 27% or more and 58% or less, and further preferably 30% or more and 55% or less.
  • the curve on the outer peripheral line of the convex portion in the vertical cross-sectional shape with respect to the length direction of the second unit lens has an angle ( ⁇ 23 ) between the tangent line and the base line at all points on the curve of 25 ° ⁇ ⁇ 23.
  • a curved portion (R 23 ) that is ⁇ 35 ° may be included.
  • Linear portion said linear angle (theta 22) of (R 22) and baseline must be within the range of less than 35 ° 25 ° or more. When there are two or more straight lines, at least one angle ( ⁇ 22 ) must satisfy this range. Further, as long as the angle ( ⁇ 22 ) is within this range, the angle of each straight line portion may be different.
  • a plane is formed as the entire unit lens and the entire optical sheet.
  • the viewing angle direction in the region immediately above the cold cathode tube of the light source device The luminance can be improved, and a decrease in luminance in the viewing angle direction in the region near the cold cathode tube of the light source device, which is generated by installing a normal lens sheet (prism sheet, lenticular sheet, etc.) can be eliminated.
  • the setting of the angle ( ⁇ 22 ) is adjusted so that it is directly above the cold cathode tube of the light source device.
  • the luminance in the viewing angle direction in the vicinity region can be improved.
  • the brightness in the viewing angle direction in the region immediately above the cold cathode tube of the light source device is improved by adjusting the setting of the angle ( ⁇ 22 ). It becomes possible to make it. If the angle ( ⁇ 22 ) is not within this range, it will be difficult to improve the luminance in the region immediately above the cold cathode tube of the light source device.
  • the shape of the entire outer periphery of the convex portion of the second unit lens is composed of a combination of the curve and the straight line.
  • the shape of the top of the outer peripheral line of the convex portion of the second unit lens may be a curved portion (see, for example, FIGS. 7 to 9), or a so-called prism shape (for example, only a straight portion) 10), or a shape in which a curved portion and a straight portion are combined.
  • the portion in contact with the base line may be either a straight line or a curved line.
  • FIG. 7 shows that the three curves of the convex portion including the top curve in the cross-sectional shape have a single elliptical shape.
  • FIG. 8 includes two curves and one straight line, and these two curves have a single elliptical shape.
  • FIG. 9 is an example in which the apex and the portion in contact with the base line have different elliptical shapes in the convex curve in the cross-sectional shape.
  • FIG. 10 is an example in which the top of the convex portion having a cross-sectional shape has a prism shape in which two straight lines are combined.
  • the distribution of the setting of the curve and the straight line is a ratio of the total length V of the convex portion outer peripheral line projected onto the lens-shaped base line and the total length W of the straight line projected onto the lens-shaped base line. It is prescribed.
  • the ratio (V: W) is preferably 15:85 or more and 85:15 or less.
  • the optimal curve and straight line ratio can be determined by the apex angle and pitch of the prism sheet.
  • the ratio (V: W) is preferably 20:80 or more and 80:20 or less, more preferably 30:70 or more and 80:20 or less, and further preferably 40:60 or more and 80:20 or less. 20 or less. If the ratio of the curve is smaller than this, sufficient light cannot be uniformly diffused to the intermediate region of the cold cathode tube array, and if it is larger than this, it becomes difficult to eliminate the dark line generated when the prism sheets are overlapped.
  • the angles ⁇ 11 and ⁇ 21 are 75 ° or more, incident light from the light source hardly reflects in the front direction at the curved portion due to reflection. Therefore, the total length projected on the base line of the portion where the angle ⁇ 11 , ⁇ 21 is 75 ° or more on the outer peripheral line of the convex portion of the unit lens vertical cross-sectional shape and the base line is 75 ° It is preferably 10% or less, more preferably 5% or less, relative to the total length of the line.
  • the setting of two or more ⁇ 11 max and ⁇ 21 max satisfying the conditions should be adjusted.
  • the combination of the optical sheet of the present invention and another optical sheet by adjusting the setting of two or more ⁇ 11 max and ⁇ 21 max satisfying the condition, in the intermediate region between adjacent cold cathode tubes. Since it becomes possible to improve the brightness
  • Ratio of height H to width P In the first or second unit lens, the length (P) of the base line and the height (H) from the base line to the lens apex in the vertical sectional shape with respect to the length direction of the unit lens
  • the ratio (H / P) is not particularly limited, but is preferably 0.25 or more and 0.75 or less, and more preferably 0.3 or more and 0.6 or less.
  • the ratio (H / P) when the ratio (H / P) is less than the above range, the composition ratio of the curved portion (R 11 ) to the curved portion (R 12 ) is reduced, and the middle of adjacent cold cathode tubes is reduced. It becomes difficult to sufficiently diffuse light into the region, and luminance in the viewing angle direction in this region cannot be improved.
  • the ratio (H / P) exceeds the above range, the ratio of the curved portion (R 12 ) to the curved portion (R 11 ) decreases, and an optical sheet such as a prism sheet or a diffusion sheet with a lens is overlaid.
  • an optical sheet such as a prism sheet or a diffusion sheet with a lens.
  • the luminance of the upper area of the cold cathode tube is insufficient, and it becomes difficult to eliminate the luminance unevenness.
  • the ratio (H / P) when the ratio (H / P) is less than the above range, the effect of the lens is reduced, and it is difficult to sufficiently diffuse light to an intermediate region between adjacent cold cathode tubes. Therefore, the luminance cannot be improved in the viewing angle direction in this region.
  • the ratio (H / P) exceeds the above range, the light is diffused to a portion beyond the intermediate region of the adjacent cold cathode fluorescent lamps, resulting in a decrease in luminance uniformity in the intermediate region.
  • the luminance uniformity in the viewing angle direction in this region is reduced.
  • the length (P) and height (H) of the unit lens may be set as appropriate according to the desired characteristics. Usually, the length (P) is 10 ⁇ m or more and 300 ⁇ m or less, and the height (H). Is 2.5 ⁇ m or more and 225 ⁇ m or less.
  • the first or second unit lens structure has an optimum shape in order to achieve high brightness uniformity. Therefore, usually other unit lens structures may be included. In order to exhibit preferable performance as the entire optical sheet, it is preferable that 50% by area or more of the entire light exit surface of the optical sheet is configured by the first unit lens and / or the second unit lens, and the structure by 60% by area or more. Is more preferable, 70% by area or more is more preferable, and 90% by area or more is more preferable. Examples of the other lens structure include a lenticular shape and a prism shape. In the unit lens structure configuration of these optical sheets, the first or second unit lens structure breakdown may be a combination configuration of the same or a combination configuration of a plurality of types of structures. In addition, it is a preferable aspect that the lens group includes only the first or second unit lens.
  • the lens group includes a unit lens (see FIG. 12) and a shape 2 having the following shape 1 as a convex portion outer peripheral line having a vertical cross-sectional shape with respect to the length direction. It has a unit lens (see FIG. 13).
  • the surface shape of the entire lens shaping surface of the optical sheet is configured by arranging at least two different types of unit lenses substantially in parallel.
  • the arrangement of the two different types of unit lenses may be arranged randomly without regularity, or may be arranged with a certain regularity.
  • the shape 1 includes a portion (R 32 ) where an angle ( ⁇ 32 ) between a tangent or straight line and a base line at all points on the curve is 25 ° ⁇ ⁇ 32 ⁇ 35 °.
  • the ratio of the total length (r 32 ) projected onto 32 baselines to the total baseline is 90% or more.
  • a cold cathode is formed when an optical sheet such as a prism sheet or a diffusion sheet with a lens generally used for increasing the luminance in the viewing angle direction is overlaid.
  • the luminance of the tube upper area is lowered, and it becomes difficult to eliminate luminance unevenness.
  • the ratio of the total (r 32 ) is more preferably 95% or more, and further preferably 100%.
  • the portion (R 32 ) occupying 90% or more of the shape 1 is composed of a straight line or a curve, and may be a combination of a plurality of straight lines and curves.
  • a so-called prism shape composed of two straight lines is one of the preferred embodiments of the present invention.
  • the curve is preferably a part of a quadratic curve, more preferably a part of a hyperbola from the viewpoints of design easiness, workability, and optical performance.
  • the shape 1 may be a left-right asymmetric shape, but is preferably left-right symmetric in order to reduce the luminance unevenness difference due to the viewing angle.
  • the shape 2 is a total of the lengths (r) projected on the base line of the unit lens shape of a portion (R 33 ) whose outer peripheral line is mainly composed of a curved portion and represented by a single quadratic curve. 33 ) is 90% or more with respect to the total length of the base line of the unit lens shape, and, as a part of the portion (R 33 ), an angle ( ⁇ between the tangent line and the base line at all points on the curve. 31), the curved portion is theta 31 ⁇ 40 ° comprises a (R 31), relative to baseline length of said portion (the lens section total length of the projected the baseline of the shape of the R 31) (r 31) The ratio is 20% or more.
  • the shape 2 has a portion (R 33 ) represented by a single quadratic curve, and the quadratic curve is preferably an ellipse or a part of a hyperbola.
  • the eccentricity is preferably 0.50 or more and 0.95 or less, more preferably 0.70 or more and 0.93 or less, and 0.80 or more and 0.90 or less. Is more preferable.
  • the shape 2 includes a curved portion (R 31 ) where the angle ( ⁇ 31 ) between the tangent line and the base line at all points on the curve is ⁇ 31 ⁇ 40 °.
  • the ratio of the total length (r 31 ) projected onto the baseline of (R 31 ) to the total length of the baseline is 20% or more.
  • the ratio of the total (r 31 ) is less than 20%, the light diffusion to the intermediate portion of the cold cathode tube array is reduced, and the luminance in the viewing angle direction at the intermediate portion is reduced, making it difficult to eliminate luminance unevenness.
  • the shape 2 may be an asymmetric shape, but is preferably left-right symmetric in order to reduce the luminance unevenness difference depending on the viewing angle.
  • the angle ( ⁇ 34 ) between the tangent line and the base line at all points on the curve is usually 25 ° ⁇ ⁇ 34 ⁇ 35 ° as a part of the portion (R 33 ). It also has a portion (R 34 ).
  • Shape 1 and shape 2 as the vertical cross-sectional shape with respect to the length direction of the unit lens in the optical sheet of the third embodiment are each a single shape as long as the above conditions are satisfied. There is no need, and the shape 1 and the shape 2 may include a plurality of types that satisfy the above-described conditions.
  • the area ratio of the unit lens having the shape 1 and the unit lens having the shape 2 is the sum of the respective projection areas on the entire light exit surface. 2) is preferably arranged to be 0.05 or more and 2.0 or less. In order to increase the luminance in the viewing angle direction when the area ratio is less than 0.05, when an optical sheet such as a commonly used prism sheet or a diffusion sheet with a lens is overlapped, Luminance decreases, and it may be difficult to eliminate luminance unevenness.
  • the area ratio is more preferably 0.1 or more and 1.5 or less, further preferably 0.15 or more and 1.0 or less, and most preferably 0.2 or more and 0.75 or less.
  • the lenses belonging to the shape 1 and the shape 2 are successively adjacent to each other while satisfying the above-described area ratio, and preferably 20 or less. More preferably.
  • the uniformity of the optical performance of the entire optical sheet is impaired, and the luminance leveling may be insufficient.
  • the layers are arranged substantially uniformly as a whole while satisfying the area ratio (shape 1 / shape 2). From the viewpoint of creating a master mold, it is most preferable to repeat the same arrangement pattern because it is easy to produce and the uniformity of the entire optical sheet is easy to design.
  • the length (P) of the base line of the outer peripheral line of the convex portion in the vertical cross-sectional shape with respect to the length direction of the unit lens is the length (L1) of the base line of the unit lens having the shape 1
  • the length (L2) of the base line of the unit lens having the shape 2 is preferably 30 ⁇ m or more and 300 ⁇ m or less, more preferably 40 ⁇ m or more and 200 ⁇ m or less, and further preferably 50 ⁇ m or more and 150 ⁇ m or less.
  • the height (H) from the base line of the convex portion outer peripheral line to the lens apex in the vertical cross-sectional shape with respect to the length direction of the unit lens has the height (H1) of the unit lens having the shape 1 and the shape 2.
  • the height (H2) of the unit lens is preferably 15 ⁇ m or more and 100 ⁇ m or less, more preferably 20 ⁇ m or more and 85 ⁇ m or more, and more preferably 25 ⁇ m or more and 65 ⁇ m or less.
  • the ratio (H / P) between the height (H) and the length (P) is not particularly limited, but as a unit lens having the shape 1, the ratio (H1 / L1) is 0.20 or more and 0.40. Or less, more preferably 0.22 or more and 0.35 or less. On the other hand, as a unit lens having the shape 2, the ratio (H2 / L2) is preferably 0.25 or more and 0.75 or less, and more preferably 0.30 or more and 0.65 or less.
  • the ratio (H / P) is less than the above range, the light diffusing effect of the lens becomes small, and the luminance uniformity may be lowered.
  • the ratio (H / P) exceeds the above range, the light diffused by the unit lens may be incident on the adjacent unit lens again and may not be emitted toward the front panel, which may reduce the luminance. There is.
  • the unit lens having the shape 1 and the unit lens having the shape 2 are optimally shaped and combined to achieve high brightness uniformity. Therefore, usually other unit lens structures may be included. In order to exhibit preferable performance as the entire optical sheet, it is preferable that 80% by area or more of the entire light exit surface of the optical sheet is constituted by the unit lens having the shape 1 and the unit lens having the shape 2; A structure of area% or more is more preferable, and a structure of 95 area% or more is more preferable.
  • the other unit lens structures may be the same combination or a plurality of combination structures.
  • the distance between the apexes of the convex portion outer peripheral lines of adjacent unit lenses is preferably 300 ⁇ m or less.
  • the luminance uniformity in the viewing angle direction is lowered, or a moire pattern is likely to occur depending on the combination with the optical sheet to be superimposed.
  • the arrangement of the lens groups arranged in the shape of the straight saddles only needs to be the arrangement ratio of the entire optical sheet.
  • the first or second unit lens, or the unit lens having the shape 1 and the unit lens having the shape 2 may be arranged at the above intervals, and other unit lenses (for example, a lenticular shape or a prism shape) may be arranged. It may be next door.
  • other unit lenses for example, a lenticular shape or a prism shape
  • the configuration of the connecting portion between adjacent unit lenses is not particularly limited as long as the target optical performance is not affected.
  • the lowest part of the outer peripheral line of the convex part in the vertical cross section with respect to the length direction of the unit lens is the base line. It is preferable that the unit lenses are aligned, that is, the unit lenses are arranged without gaps.
  • a gap may be provided between each unit lens as long as it does not affect the optical performance of the entire optical sheet.
  • a slight gap is given so as to facilitate release after the lens shape transfer.
  • any shape such as a straight line, a concave curve, or a V-shape can be used as long as the optical performance is not affected.
  • the invention is synonymous with no gap.
  • thermoplastic resin constituting the optical sheet of the present invention is not particularly limited as long as it is transparent and has an appropriate strength as a main component of the optical sheet.
  • thermoplastic resin for example, polycarbonate resin; acrylic resin such as polymethyl methacrylate; styrene resin such as polystyrene, polyvinyl toluene, poly (p-methylstyrene); MS resin (copolymer of methyl methacrylate and styrene); norbornene resin Polyolefin resin; Polyarylate resin; Polyethersulfone resin Among these, two or more kinds of mixed resins can be used.
  • a polycarbonate resin, a styrene resin, or a norbornene resin is preferably used.
  • polycarbonate resin is particularly preferable as a resin for an optical sheet because it is excellent in transparency, heat resistance, and workability and has a good balance.
  • the thermoplastic resin may contain an ultraviolet absorber, a fluorescent whitening agent, a flame retardant, and the like as necessary.
  • the optical sheet of the present invention may be composed only of a transparent resin, but in order to adjust light diffusibility, a light diffusion layer made of particles having light diffusibility may be provided.
  • the light diffusing layer may be uniformly or randomly dispersed in the entire optical sheet, only the lens portion, the entire portion other than the lens portion, only the light exit surface layer, only the light entrance surface layer, or the intermediate layer.
  • light diffusing particles having a refractive index of 0.01 or more different from that of a transparent resin are dispersed in a thermoplastic resin. It has adjustment effects such as direction and diffusion ratio, and it is possible to further increase the brightness uniformity in the viewing angle direction.
  • the support pin image can be erased even when the number of sheets used is reduced.
  • Light diffusing agent examples include (meth) acrylic resins, styrene resins, polyurethane resins, polyester resins, silicone resins, fluororesins, and copolymers thereof. Glass; clay compounds such as smectite and kaolinite; inorganic oxides such as silica and alumina; and the like. Of these materials, (meth) acrylic resins, silicone resins, and silica are particularly suitable.
  • the light diffusing agent may be a single material, a mixture of single materials, a mixed material, or a mixture of mixed materials of these exemplified materials.
  • (meth) acryl means acryl and / or methacryl.
  • the average particle size of the light diffusing particles is preferably from 0.1 ⁇ m to 50 ⁇ m, more preferably from 0.3 ⁇ m to 10 ⁇ m, and even more preferably from 0.5 ⁇ m to 5 ⁇ m.
  • the average particle diameter of the light diffusing particles is a volume-based median diameter measured by a particle size distribution measuring device (Coulter counter).
  • the ratio between the thermoplastic resin and the light diffusing particles may be adjusted as appropriate. For example, if the light diffusing particles are added in an amount of 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin. Good. When the amount of the light diffusing particles is less than 0.01 parts by mass, the luminance uniformity adjustment by the light diffusing agent cannot be sufficiently performed. On the other hand, if the light diffusing particles exceed 10 parts by mass, the transparency of the light diffusing layer may be lowered, and the brightness of the entire optical sheet may be lowered.
  • low crosslink density organic fine particles capable of exhibiting anisotropic light diffusibility during the molding of the optical sheet are preferably used.
  • Raw material monomers for the low crosslink density organic fine particles include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n- Butyl (meth) acrylate, iso-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxy (Meth) acrylates such as propyl (meth) acrylate;
  • Low crosslinking density organic fine particle crosslinking agents include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and trimethylolpropane tri (meth).
  • Polyfunctional (meth) acrylates such as acrylate and bishydroxyethyl bisphenol A di (meth) acrylate; radical polymerizable crosslinking agents such as divinyloxyethoxy (meth) acrylate, diallyl phthalate, allyl (meth) acrylate, and divinylbenzene; bisphenol Polyfunctional epoxy compounds such as A diglycidyl ether, diethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether; tolylene diisocyanate, Siri diisocyanate, polyfunctional isocyanate compounds such as isophorone diisocyanate; N- methylol melamine, polyfunctional methylol compounds such as N- methylol benzoguanamine; one, or may be used in combination of two or more thereof.
  • radical polymerizable crosslinking agents such as divinyloxyethoxy (meth) acrylate, diallyl phthalate, allyl (meth)
  • the crosslink density of the low crosslink density organic fine particles for achieving anisotropic light diffusion performance is preferably 0.001% or more and 0.12% or less.
  • Such organic fine particles having a low cross-linking density are spherical or substantially spherical at the raw material stage, but are formed into an ellipsoidal shape or a rod shape at a predetermined position (layer, etc.) of the optical sheet due to heat, shearing force, etc. received during molding of the optical sheet. When this shape is changed, anisotropic diffusivity is expressed.
  • a crosslinking density is a numerical value calculated
  • Fn (c) number of functional groups of the crosslinking agent used for producing the radical polymer-based crosslinked fine particles Mw (c): molecular weight of the crosslinking agent used for producing the radical polymer-based crosslinked fine particles W (c): crosslinking agent used for producing the radical polymer-based crosslinked fine particles Mass blending ratio (%) W (m): Mass blending ratio (%) of monomer used for production of radical polymerized crosslinked fine particles
  • Antioxidant An antioxidant may be further blended in at least one of the organic fine particles including the low crosslink density organic fine particles of the present invention or the thermoplastic resin. Since the antioxidant can suppress coloring of the thermoplastic resin and organic fine particles due to oxidation and deterioration during thermoforming, the brightness of the backlight device to which the optical sheet of the present invention is applied can be more reliably exhibited. .
  • antioxidant a conventionally known antioxidant can be used.
  • octadecyl-3- (3,5-di-t-butyl-1-hydroxyphenyl) propionate etc.
  • Hindered phenolic antioxidants tris (2,4-di-t-butylphenyl) phosphite, tris [2-[[2,4,8,10-tetra-t-butyldibenzo [d, f] [ Phosphorous antioxidants such as 1,3,2] dioxaphosphine-6-yl] oxy] ethyl] amine; thiodiethylenebis [3- (3,5-di-t -Butyl-4-hydroxyphenyl) propionate] and the like having no aromatic ring, pentaerythrityltetrakis (3-laurylthiopropionate) Sulfur-based antioxidants such as; lactone-based antioxidants such as the reaction product of 3-hydroxy-5,7-di-t-butyl-furan-2-one and o-xylene; Hydroxylamine antioxidants such as oxidation products of alkylamines; 3,4-dihydro-2,5,7,8-tetra
  • the amount of the antioxidant used may be adjusted as appropriate, but it is usually sufficient to add about 0.005 mass% or more and 0.3 mass% or less with respect to the thermoplastic resin. That is, an antioxidant may be added in an amount of about 0.005 parts by mass to about 0.3 parts by mass with respect to 100 parts by mass of the thermoplastic resin.
  • the thickness of the optical sheet of the present invention can be adjusted as appropriate and is not particularly limited, but can usually be about 0.3 mm or more and 10 mm or less. If the thickness of the optical sheet is less than 0.3 mm, the light diffusing action may not be sufficiently exhibited, or the rigidity may be insufficient to maintain the shape stability. On the other hand, if the thickness of the optical sheet exceeds 10 mm, the entire apparatus to which the optical sheet of the present invention is applied may not be made compact. More preferably, the thickness of the optical sheet is 0.5 mm or more and 5 mm or less. The thickness of the optical sheet is the sum of the thickness of the base and the unit lens height (see FIGS. 4, 5, and 11).
  • the optical sheet of the present invention can be manufactured by using a matrix facing a predetermined surface shape.
  • the shape of the matrix is a shape for the lens group of the obtained optical sheet to realize the predetermined surface shape defined in the present invention, that is, the convex portion of these surface shapes is concave and the concave portion is convex. Any structure can be used.
  • the matrix having these structures is referred to as a “facing matrix for forming the surface shape” (see FIGS. 14 and 15).
  • the optical sheet of the present invention can be manufactured by a manufacturing process having the matrix. Specifically, it can be obtained by known extrusion molding or injection molding using a transparent thermoplastic resin or a mixture of transparent thermoplastic resin and fine particles having light diffusibility.
  • a laminated body is used to adjust optical performance and other physical properties (for example, when a light diffusing layer is installed only on a specific layer such as a light incident side or a lens side, or UV light for improving the light resistance of an optical sheet)
  • the extrusion method is particularly preferable from the viewpoint of productivity. Further, it is particularly preferable to use the method described in Japanese Patent Application No. 2008-249254 when shaping a lens shape having a narrow pitch.
  • a molded product according to the design of the present invention can be manufactured can be confirmed by obtaining x 1 and x 2 from the molded product. Specifically, a vertical cross-sectional shape with respect to the length direction of the unit lens is photographed with an electron microscope or the like, and an appropriate curve (a plurality of combinations may be used) with respect to the curved portion in the outer peripheral line of the convex portion. ) And the angle between the tangent line and the base line is determined from the range of the outer peripheral line, and for the straight line portion, the range of the outer peripheral line where the angle at which the straight line is the base line is the predetermined angle. Ask from.
  • the optical sheet of the present invention is preferably used as the first optical sheet in order to efficiently use its high optical performance adjustment capability in other optical sheets and apparatus settings.
  • the effect of improving the luminance in the viewing angle direction in the intermediate region of the adjacent cold cathode tubes of the light source device and the luminance in the viewing angle direction in the region immediately above the cold cathode tube are improved.
  • the effect can be utilized to the maximum.
  • the other optical sheet can be a prism sheet, a diffusion sheet, a microlens sheet, etc., and the combination is also selected according to the conditions of the light source device.
  • a diffusion sheet as the optical sheet closest to the front panel.
  • the use of at least one prism sheet for the second and subsequent optical sheets eliminates dark lines generated near the cold cathode tube and achieves high brightness and brightness uniformity on the light exit surface immediately before the front panel. It becomes possible.
  • the optical sheet of the present invention exhibits excellent light diffusion performance when used in combination with a prism sheet, the pattern of the line light source can be erased even if the number of optical sheets used is reduced to three. Become. Thus, it has been found that the image of the support pin becomes noticeable only for the first time by reducing the number of sheets used to 3 using the optical sheet of the present invention.
  • the optical sheet of the present invention has a light diffusing layer, in the direct type light source device, the performance of erasing the image of the support pins that support the optical sheet is also improved. Accordingly, when the optical sheet of the present invention has a light diffusing layer, it is also a preferable aspect to use only three sheets of the optical sheet, the prism sheet and the light diffusing sheet of the present invention.
  • the optical sheet manufactured according to the present invention can diffuse light in a desired direction, and as a result, can maintain the uniformity of the light, thereby reducing the manufacturing cost of the liquid crystal display device, which is in increasing demand. It is extremely useful industrially as a material that can exhibit high brightness. Therefore, the manufacturing cost can be reduced by applying the optical sheet of the present invention and the direct light source device having the optical sheet to a liquid crystal display device or the like.
  • a white reflective plate is provided on the inner surface of a plastic case having an inner width of 690 mm, a depth of 390 mm, and a depth of 10 mm, and a cold cathode tube having a diameter of 3 mm at a position 3.5 mm away from the bottom of the reflector.
  • a direct type light source device in which 19 pieces were arranged in parallel at intervals of 20.5 mm was used.
  • the optical sheets of the present invention having various shapes were arranged such that the lens processing surface was on top and the longitudinal direction of the lens was parallel to the longitudinal direction of the cold cathode tube.
  • a commercially available light diffusing sheet (CH273 manufactured by Hiroshige Kogyo (Suzhou) Co., Ltd.), prism sheet (BEF II 90/50 manufactured by Sumitomo 3M: apex angle 90 degrees, pitch 50 ⁇ m), microlens sheet ( ML24M manufactured by Hiroshige Kogyo (Suzhou) Co., Ltd .: an optical sheet in which hemispherical convex lens groups are finely arranged on one surface) was placed according to the combinations shown in Table 4. In each combination, luminance unevenness was visually observed from a position 400 mm away from the center of the direct light source device in the vertical direction. The brightness unevenness is evaluated in 10 stages, and the larger the value, the less the brightness unevenness, indicating that the lamp image of the cold cathode tube is not noticeable. The evaluation results are shown in Tables 1 to 3.
  • the length (x 1 ), length (x 2 ) of each unit lens constituting the lens group, and the total (x 1total ) and total (x 2total ) of the entire lens group are summarized in Table 5.
  • the total (x 1total ) is 25% to 60% of the total length (P total ) of the baseline of the lens group, and the total (x 2Total ) is the length of the baseline of the lens group
  • Examples 1 to 35 that are 25% to 60% of the total (P total ) are used, the luminance unevenness is small in any combination shown in Table 4.
  • a white reflective plate is provided on the inner surface of a plastic case with an inner dimension width of 690 mm, a depth of 390 mm, and a depth of 25 mm, and a cold 3 mm diameter is placed at a position 5 mm away from the bottom of the reflector.
  • a direct type light source device in which eight cathode tubes were arranged in parallel at intervals of 45 mm and support pins were arranged as shown in FIG. 30 was used.
  • the optical sheets of the present invention having various shapes were arranged such that the lens processing surface was on top and the longitudinal direction of the lens was parallel to the longitudinal direction of the cold cathode tube.
  • a prism sheet (BEF II 90/50: vertical angle 90 degrees, pitch 50 ⁇ m, manufactured by Sumitomo 3M) is placed on this optical sheet, and a microlens sheet (manufactured by Hiroshige Kogyo (Suzhou) Co., Ltd.) ML24M: one side
  • An optical sheet in which hemispherical convex lens groups are finely arranged is placed on the surface.
  • the support pin image and the luminance unevenness were visually observed from a position 400 mm away from the center of the direct light source device in the vertical direction.
  • the support pin image when it was confirmed visually, it was judged as “bad”, when it was confirmed partially, “good”, and when it could not be confirmed at all, “excellent”.
  • the brightness unevenness is evaluated in 10 stages, and the larger the value, the less the brightness unevenness, indicating that the lamp image of the cold cathode tube is not noticeable. The evaluation results are shown in Table 6.
  • Example 13 is an optical sheet in which the total (x 1Total ) and the total (x 2Total ) are within the specified range of the present invention, and a light diffusion layer is provided.
  • the support pin image can be erased by the group of three optical sheets, and luminance unevenness is small.
  • the first optical sheet capable of improving the luminance ratio at the intermediate point between the line light sources arranged in parallel with each other and / or directly above the cold cathode tube, and obtaining a uniform luminance distribution;
  • a direct light source device and a liquid crystal display device can be provided, which is extremely useful in industry.

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  • Liquid Crystal (AREA)

Abstract

Provided is an optical sheet for liquid crystal display panels enabling improvement of the luminance ratios at the center points between linear light sources arranged next to each other and positions directly above the linear light sources and uniform luminance distribution.  A method of manufacturing the optical sheet, a directly-below light source, and a liquid crystal display device are also provided.  The optical sheet including convex lenses formed in linear ridge shapes on its surface is characterized in that the outer line of the ridges of all the lenses shown in the cross section taken perpendicularly to their lengthwise directions is composed of curves and/or lines, and include at a predetermined ratio parts (X1) satisfying that the angles (θ) formed by tangent lines at all the points on the curves and/or by the lines and base lines are θ ≥ 40° and parts (X2) where the angles (θ) are 25°≤ θ ≤35°.

Description

光学シートおよび当該光学シートの製造方法、並びに当該光学シートを含む光源装置、表示装置OPTICAL SHEET, METHOD FOR PRODUCING OPTICAL SHEET, LIGHT SOURCE DEVICE AND DISPLAY DEVICE INCLUDING OPTICAL SHEET
本発明は、光学シート、および当該光学シートの製造方法、および当該光学シートを含む光源装置、並びに表示装置に関するものである。 The present invention relates to an optical sheet, a method for manufacturing the optical sheet, a light source device including the optical sheet, and a display device.
　近年、表示装置はブラウン管を用いたものから液晶を用いたものに代わってきており、また、画面も大型化してきている。液晶表示装置の光源としてはエッジライト方式と直下型方式のものがあるが、大型の液晶表示装置では、光源として複数の冷陰極管を配置した直下型光源が一般的に用いられている。 In recent years, display devices have been changed from those using cathode ray tubes to those using liquid crystals, and the screens have also become larger. The light source of the liquid crystal display device includes an edge light type and a direct type, but a large type liquid crystal display device generally uses a direct type light source in which a plurality of cold cathode tubes are arranged as the light source.
　直下型光源を用いた液晶表示装置の画面では、冷陰極管が存在する部分は明るいが、一方で冷陰極管が存在しない部分は比較的暗いという輝度ムラが生じ、また、冷陰極管が画面に映り込むという問題がある。そこで、冷陰極管と液晶パネルとの間に各種光学シートを配置することにより、冷陰極管から発せられる光を画面全体にわたり均一に拡散させることが行われている。 On the screen of a liquid crystal display device using a direct type light source, the portion where the cold-cathode tube is present is bright, while the portion where the cold-cathode tube is not present is relatively dark, resulting in uneven brightness. There is a problem of being reflected in. Therefore, by arranging various optical sheets between the cold cathode fluorescent lamp and the liquid crystal panel, light emitted from the cold cathode fluorescent lamp is uniformly diffused over the entire screen.
　液晶表示装置は一層の薄肉化が要求されており、そのために冷陰極管と画面との距離を狭めざるを得ず、冷陰極管からの光を十分に拡散させることが困難になってきている。また、コストを下げるために冷陰極管の数を減らすことも行われており、冷陰極管間隔の拡大にともなって冷陰極管からの光を均一に拡散させることが困難になってきている。そのため、このような厳しい条件下で、輝度ムラを解消させ輝度を向上させる方法としては、光源に最も近い位置に配される光学シートにレンズ付光学シートを選択し、そのレンズ形状を調整することが行われている。さらに輝度の観点から、光源から液晶パネル側の方向に対して、２番目以降に配される光学シートには、少なくとも１枚のプリズムシートが選択されている。このような、複数の光学シートの組合せにおいて課題となるのは、第一に冷陰極管が存在する部分は明るいが、冷陰極管が存在しない部分は比較的暗いという輝度ムラの解消と、第二にレンズ付拡散シートやプリズムシートを用いることで発生する冷陰極管直上近傍の低輝度部に起因する新たな輝度ムラをも解消することである。 Liquid crystal display devices are required to be further thinned. For this reason, the distance between the cold cathode fluorescent lamp and the screen has to be narrowed, and it has become difficult to sufficiently diffuse the light from the cold cathode fluorescent lamp. . Further, in order to reduce the cost, the number of cold cathode tubes is also reduced, and it is difficult to uniformly diffuse light from the cold cathode tubes as the interval between the cold cathode tubes is increased. Therefore, under such severe conditions, as a method of eliminating luminance unevenness and improving luminance, select an optical sheet with a lens as the optical sheet placed closest to the light source and adjust the lens shape. Has been done. Further, from the viewpoint of luminance, at least one prism sheet is selected as the second and subsequent optical sheets with respect to the direction from the light source to the liquid crystal panel. The problem in the combination of a plurality of optical sheets is that, in the first place, the portion where the cold-cathode tube is present is bright, but the portion where the cold-cathode tube is not present is relatively dark, and the unevenness of brightness is reduced. Secondly, it is also possible to eliminate new brightness unevenness caused by the low brightness portion near the cold cathode tube which is generated by using a diffusion sheet with a lens or a prism sheet.
　照明効率の低減を防止しつつ、輝度分布を均一にするために、例えば、特許文献１、特許文献２で開示された直下型光源装置では、横断面が三角形である複数のプリズムレンズが並設されたプリズムシートや、凸面が円筒面である複数のシリンドリカルレンズが並設されたレンチキュラレンズシートを、従来の光学シートの代替として使用している。プリズムシートやレンチキュラレンズシートは、従来タイプの光拡散剤による光学シートと比較して、入射された光線が反射屈折を繰り返す回数が少ないため、透過光量の減少を防止でき、視野角方向での輝度を向上できる。しかしながら、プリズムシートは、輝度を向上させることが可能であるがその分布の均一化に限界がある。レンチキュラレンズシートも、プリズムシートよりも輝度分布の均一度を高めることができるものの、上記のような厳しい冷陰極管の設置条件では、完全な輝度ムラ解消は困難である。 In order to make the luminance distribution uniform while preventing a reduction in illumination efficiency, for example, in the direct light source device disclosed in Patent Literature 1 and Patent Literature 2, a plurality of prism lenses having a triangular cross section are arranged in parallel. A prism sheet or a lenticular lens sheet in which a plurality of cylindrical lenses having a cylindrical convex surface are arranged in parallel is used as an alternative to a conventional optical sheet. Prism sheets and lenticular lens sheets can prevent the amount of transmitted light from decreasing and the brightness in the viewing angle direction because the number of incident rays repeats catadioptric refraction is less than optical sheets with conventional light diffusing agents. Can be improved. However, although the prism sheet can improve the luminance, there is a limit to the uniform distribution thereof. Although the lenticular lens sheet can also increase the uniformity of the luminance distribution as compared with the prism sheet, it is difficult to completely eliminate the luminance unevenness under the severe cold cathode tube installation conditions as described above.
特開平１０－２８３８１８号公報JP-A-10-283818 特開２００４－００６２５６号公報JP 2004006256 A
　出光面に直線畝状に配されたレンズを有する光学シートを光源に最も近い位置に配し、光源から液晶パネル側の方向に対して２番目以降に配される光学シートに少なくとも１枚のプリズムシートなどを用いると、プリズムの効果により光拡散性が高められ、しかも正面輝度を上昇させることができる。そのため、液晶テレビの薄型化や、冷陰極管の本数削減に最適な光源用光学シート構成と考えられている。 An optical sheet having lenses arranged in a straight bowl on the light exit surface is arranged at a position closest to the light source, and at least one prism is provided on the optical sheet arranged second or later in the direction from the light source to the liquid crystal panel. When a sheet or the like is used, the light diffusibility is enhanced by the effect of the prism, and the front luminance can be increased. Therefore, it is considered to be an optical sheet configuration for a light source that is optimal for thinning a liquid crystal television and reducing the number of cold cathode tubes.
　しかしながら、このような光学シート構成は、本来なら輝度が低い冷陰極管の間へ充分な光を拡散させることができるものの、光学シートからプリズムシートへの入射角の浅い光はプリズムシートによって、光学シートへ戻されるため、冷陰極管上に暗線が発生する。冷陰極管のパターンを消去できても、この暗線が残存してしまうため、新たな輝度ムラが発生する。 However, although such an optical sheet configuration can diffuse sufficient light between cold cathode tubes with originally low brightness, light with a small incident angle from the optical sheet to the prism sheet is optically reflected by the prism sheet. Since the sheet is returned to the sheet, a dark line is generated on the cold cathode tube. Even if the pattern of the cold-cathode tube can be erased, this dark line remains, resulting in new brightness unevenness.
　また、さらなるコスト低減のため、光源装置に使用する光学シートの枚数を減らすことが求められている。ここで、光学シートの使用枚数を減らした場合、輝度ムラの解消がより困難になるだけでなく、バックライトユニットにおいて光学シートを支えるピンのイメージが現れるという新たな問題が生じてきた。 Also, for further cost reduction, it is required to reduce the number of optical sheets used in the light source device. Here, when the number of used optical sheets is reduced, it becomes more difficult to eliminate luminance unevenness, and a new problem has arisen that an image of a pin that supports the optical sheet appears in the backlight unit.
　本発明の目的は、互いに並設された線光源（例えば、冷陰極管）間の中間地点および線光源直上における輝度ムラを低減し、光源から液晶パネル側の方向に対して２番目以降に配される光学シートとの組合せにより均一な輝度分布を得ることができる光学シート、および当該光学シートの製造方法、並びにそれらを含む光源装置、液晶表示装置を提供することである。 An object of the present invention is to reduce luminance unevenness at an intermediate point between line light sources (for example, cold-cathode tubes) arranged in parallel with each other and directly above the line light source, and to be arranged second or later in the direction from the light source to the liquid crystal panel. It is to provide an optical sheet capable of obtaining a uniform luminance distribution by combination with the optical sheet, a manufacturing method of the optical sheet, a light source device including them, and a liquid crystal display device.
　上記課題および従来技術の問題点を解消すべく、鋭意検討を重ねた結果、発明者らは、光学シート表面に直線畝状に形成されたレンズ群において、該レンズ群の長さ方向に対する垂直断面形状における全てのレンズの凸状部外周線が曲線および／または直線で構成され、前記曲線の接線および／または前記直線と基底線のなす角度が、特定の範囲内となる部分の割合を調節することにより、上記課題が解決されることを見出し、発明を完成するに至った。 As a result of intensive studies to solve the above problems and the problems of the prior art, the inventors have obtained a cross section perpendicular to the length direction of the lens group in the lens group formed in a linear bowl shape on the surface of the optical sheet. The outer peripheral line of the convex part of all the lenses in the shape is composed of a curve and / or a straight line, and the tangent line of the curve and / or the angle formed by the straight line and the base line adjusts the ratio of the part within a specific range. As a result, the inventors have found that the above problems can be solved, and have completed the invention.
　すなわち、本発明の光学シートは、表面に直線畝状に形成された凸状のレンズ群を有する光学シートであって、該レンズ群の長さ方向に対する垂直断面形状における全てのレンズの凸状部外周線が、曲線および／または直線で構成され、かつ、前記曲線上の全ての点における接線および／または前記直線と基底線のなす角度（θ）がθ≧４０°である部分（Ｘ1）と、前記曲線上の全ての点における接線および／または前記直線と基底線のなす角度（θ）が２５°≦θ≦３５°である部分（Ｘ2）を含み、前記部分（Ｘ1）の前記レンズ群の基底線に投影した長さ（ｘ1）の総計（ｘ1total）が、前記レンズ群の基底線の長さの総計（Ｐtotal）の２５％以上６０％以下であり、かつ、前記部分（Ｘ2）の該レンズ群の基底線に投影した長さ（ｘ2）の総計（ｘ2total）が、前記レンズ群の基底線の長さの総計（Ｐtotal）の２５％以上６０％以下であることを特徴とする。 That is, the optical sheet of the present invention is an optical sheet having a convex lens group formed on the surface in the form of a straight bowl, and the convex parts of all the lenses in a cross-sectional shape perpendicular to the length direction of the lens group. A portion (X 1 ) in which the outer peripheral line is composed of a curve and / or a straight line and the angle (θ) between the tangent and / or the straight line and the base line at all points on the curve is θ ≧ 40 ° And a portion (X 2 ) where an angle (θ) formed between a tangent at all points on the curve and / or the straight line and a base line is 25 ° ≦ θ ≦ 35 °, and the portion (X 1 ) The total length (x 1total ) of the length (x 1 ) projected on the base line of the lens group is 25% or more and 60% or less of the total length (P total ) of the base line length of the lens group, and said portion (X 2) the lens group length projected in baseline of (x 2 Total (x 2total), characterized in that the total length of the lens group of the base line is 60% or less 25% or more (P total).
　本発明の第一の実施態様は、前記レンズ群が、単位レンズの長さ方向に対する垂直断面形状における凸状部外周線が曲線を主体に構成され、かつ、前記曲線上の全ての点における接線と基底線のなす角度（θ11）がθ11≧４０°である曲線部（Ｒ11）と、その曲線上の全ての点における接線と基底線のなす角度（θ12）が２５°≦θ12≦３５°である曲線部（Ｒ12）を含み、前記曲線部（Ｒ11）の該単位レンズ形状の基底線に投影した長さの総計（ｒ11）の前記基底線の全長に対する割合が２５％以上６０％以下であり、かつ、前記曲線部（Ｒ12）の該単位レンズ形状の基底線に投影した長さの総計（ｒ12）の前記基底線の全長に対する割合が２５％以上６０％以下である第１単位レンズ（図６参照）を有する光学シートである。 In the first embodiment of the present invention, the lens group is configured such that the convex outer peripheral line in the vertical cross-sectional shape with respect to the length direction of the unit lens is mainly composed of a curve, and tangents at all points on the curve and the angle of the baseline (theta 11) is the theta 11 ≧ 40 ° curved section and (R 11), the tangent angle of the base line at all points on the curve (theta 12) is 25 ° ≦ theta The ratio of the total length (r 11 ) of the curved portion (R 11 ) projected onto the base line of the unit lens shape to the total length of the base line includes the curved portion (R 12 ) satisfying 12 ≦ 35 °. The ratio of the total length (r 12 ) of the curved portion (R 12 ) projected onto the base line of the unit lens shape to the total length of the base line is 25% or more and 60% or less. % Is an optical sheet having a first unit lens (see FIG. 6) that is less than or equal to%.
　本発明の第二の実施態様は、前記レンズ群が、単位レンズの長さ方向に対する垂直断面形状における凸状部外周線が２つ以上の曲線と１つ以上の直線が連結した形状から構成され、かつ、前記曲線の少なくとも２つが、その曲線上の全ての点における接線と基底線のなす角度（θ21）がθ21≧４０°である曲線部（Ｒ21）を含み、前記直線（Ｒ22）と基底線のなす角度（θ22）が２５°≦θ22≦３５°である第２単位レンズ（図７～図１０参照）を有する光学シートである。 In the second embodiment of the present invention, the lens group is formed of a shape in which the convex portion outer peripheral line in the vertical cross-sectional shape with respect to the length direction of the unit lens is formed by connecting two or more curves and one or more straight lines. And at least two of the curves include a curve portion (R 21 ) in which an angle (θ 21 ) between a tangent line and a base line at all points on the curve is θ 21 ≧ 40 °, and the straight line (R 22 ) and a base line (θ 22 ) is an optical sheet having a second unit lens (see FIGS. 7 to 10) in which 25 ° ≦ θ 22 ≦ 35 °.
　本発明の第三の実施態様は、前記レンズ群が、長さ方向に対する垂直断面形状の凸状部外周線として、下記の形状１を有する単位レンズ（図１２参照）および形状２を有する単位レンズ（図１３参照）を有する光学シートである。
　≪形状１≫
　外周線が曲線または直線からなり、かつ、その曲線上の全ての点における接線または直線と該単位レンズ断面形状の基底線がなす角度（θ32）が２５°≦θ32≦３５°である部分（Ｒ32）を含み、前記部分（Ｒ32）の該単位レンズ断面形状の基底線に投影した長さの総計（ｒ32）が、該単位レンズ断面形状の基底線全長に対して９０％以上であることを特徴とする形状。
　≪形状２≫
　外周線が曲線部を主体に構成され、かつ、単一の二次曲線で表される部分（Ｒ33）の該単位レンズ形状の基底線に投影した長さの総計（ｒ33）が、該単位レンズ形状の基底線全長に対して９０％以上であり、かつ前記部分（Ｒ33）の一部として、その曲線上の全ての点における接線と基底線のなす角度（θ31）が、θ31≧４０°である曲線部（Ｒ31）を含み、前記部分（Ｒ31）の該レンズ断面形状の基底線に投影した長さの総計（ｒ31）の基底線全長に対する割合が２０％以上であることを特徴とする形状。
　また、本発明には、前記光学シートの製造方法、前記光学シートとプリズムシートを必須とする表示装置用光源装置および該表示装置用光源装置を含む表示装置も含まれる。 According to a third embodiment of the present invention, the lens group includes a unit lens (see FIG. 12) having the following shape 1 and a unit lens having the shape 2 as a convex portion outer peripheral line having a vertical cross-sectional shape with respect to the length direction. It is an optical sheet having (see FIG. 13).
≪Shape 1≫
A portion in which an outer peripheral line is a curve or a straight line, and an angle (θ 32 ) between a tangent or a straight line at all points on the curve and a base line of the unit lens cross-sectional shape is 25 ° ≦ θ 32 ≦ 35 ° (R 32 ), and the total length (r 32 ) of the portion (R 32 ) projected onto the base line of the unit lens cross-sectional shape is 90% or more with respect to the total base line length of the unit lens cross-sectional shape A shape characterized by
≪Shape 2≫
The total length (r 33 ) projected on the base line of the unit lens shape of the portion (R 33 ) whose outer peripheral line is mainly composed of a curved portion and is represented by a single quadratic curve, The angle (θ 31 ) between the tangent line and the base line at all points on the curve is 90% or more with respect to the total length of the base line of the unit lens shape and is a part of the portion (R 33 ). The ratio (r 31 ) of the total length (r 31 ) projected to the base line of the lens cross-sectional shape of the part (R 31 ) is 20% or more including the curved line part (R 31 ) where 31 ≧ 40 ° A shape characterized by
The present invention also includes a method for manufacturing the optical sheet, a light source device for a display device that requires the optical sheet and a prism sheet, and a display device that includes the light source device for the display device.
　本発明の光学シートを用いることにより、光源装置の線光源直上近傍領域における視野角方向での輝度と、隣り合う線光源の中間領域における視野角方向での輝度を各々独立して調整することが可能となる。そのため、様々な装置設定（装置構成、光源装置条件、本発明以外の光学シートとの組合せ）において、その設定における出光面側の高輝度均整度が実現できる。 By using the optical sheet of the present invention, the luminance in the viewing angle direction in the region immediately above the line light source of the light source device and the luminance in the viewing angle direction in the intermediate region of the adjacent line light sources can be independently adjusted. It becomes possible. Therefore, in various apparatus settings (apparatus configuration, light source apparatus conditions, combinations with optical sheets other than the present invention), high brightness uniformity on the light exit surface side in the settings can be realized.
表示装置の構成を示す模式図である。It is a schematic diagram which shows the structure of a display apparatus. 本発明の光学シートであって、第二の実施態様を示す図である。It is an optical sheet of this invention, Comprising: It is a figure which shows a 2nd embodiment. 本発明の光学シートであって、第三の実施態様を示す図である。It is an optical sheet of this invention, Comprising: It is a figure which shows a 3rd embodiment. 第一の実施態様の光学シートの各部の名称の説明図である。It is explanatory drawing of the name of each part of the optical sheet of a 1st embodiment. 第二の実施態様の光学シートの各部の名称の説明図である。It is explanatory drawing of the name of each part of the optical sheet of a 2nd embodiment. 第１単位レンズ表面形状設計概念の一例説明図である。It is an example explanatory drawing of the 1st unit lens surface shape design concept. 第２単位レンズ形状の一例の説明図である。It is explanatory drawing of an example of a 2nd unit lens shape. 第２単位レンズ形状の一例の説明図である。It is explanatory drawing of an example of a 2nd unit lens shape. 第２単位レンズ形状の一例の説明図である。It is explanatory drawing of an example of a 2nd unit lens shape. 第２単位レンズ形状の一例の説明図である。It is explanatory drawing of an example of a 2nd unit lens shape. 第三の実施態様の光学シートの各部の名称の説明図である。It is explanatory drawing of the name of each part of the optical sheet of a 3rd embodiment. 単位レンズ断面形状１の一例の説明図である。It is explanatory drawing of an example of unit lens cross-sectional shape 1. FIG. 単位レンズ断面形状２の一例の説明図である。It is explanatory drawing of an example of unit lens cross-sectional shape 2. FIG. 第一および第二の実施態様の光学シートの製造方法に用いられる表面形状を形成する為の正対する母型の一例の説明図である。It is explanatory drawing of an example of the matrix which faces directly for forming the surface shape used for the manufacturing method of the optical sheet of the 1st and 2nd embodiment. 第三の実施態様の光学シートの製造方法に用いられる表面形状を形成する為の正対する母型の一例の説明図である。It is explanatory drawing of an example of the matrix which faces directly for forming the surface shape used for the manufacturing method of the optical sheet of a 3rd embodiment. 実施例１～６における第１単位レンズ表面形状の説明図である。FIG. 7 is an explanatory diagram of a surface shape of a first unit lens in Examples 1 to 6. 実施例７における第１単位レンズ表面形状の説明図である。FIG. 10 is an explanatory diagram of a surface shape of a first unit lens in Example 7. 実施例８における第１単位レンズ表面形状の説明図である。FIG. 10 is an explanatory diagram of a surface shape of a first unit lens in Example 8. 実施例９における第１単位レンズ表面形状の説明図である。FIG. 14 is an explanatory diagram of a surface shape of a first unit lens in Example 9. 実施例１０における第１単位レンズ表面形状の説明図である。FIG. 14 is an explanatory diagram of a first unit lens surface shape in Example 10. 実施例１１における第１単位レンズ表面形状の説明図である。FIG. 12 is an explanatory diagram of a surface shape of a first unit lens in Example 11. 実施例１２，１３における第１単位レンズ表面形状の一例の説明図である。It is explanatory drawing of an example of the 1st unit lens surface shape in Examples 12 and 13. FIG. 実施例１４の光学シートのレンズ群の説明図である。FIG. 22 is an explanatory diagram of a lens group of the optical sheet of Example 14. 比較例５の光学シートのレンズ群の説明図である。10 is an explanatory diagram of a lens group of an optical sheet of Comparative Example 5. FIG. 実施例２７の光学シートのレンズ群の説明図である。42 is an explanatory diagram of a lens group of an optical sheet according to Example 27. FIG. 実施例２８～３３における単位レンズ断面形状１の一例の説明図である。FIG. 22 is an explanatory diagram of an example of a unit lens cross-sectional shape 1 in Examples 28 to 33. 実施例２８～３５における単位レンズ断面形状２の一例の説明図である。FIG. 22 is an explanatory diagram of an example of a unit lens cross-sectional shape 2 in Examples 28 to 35. 実施例３４，３５における単位レンズ断面形状１の一例の説明図である。It is explanatory drawing of an example of the unit lens cross-sectional shape 1 in Example 34,35. 実施例２８～３３の光学シートのレンズ群の説明図である。FIG. 42 is an explanatory diagram of a lens group of an optical sheet according to Examples 28 to 33. 実施例で用いた直下型光源装置における支持ピンの配置の説明図である。It is explanatory drawing of arrangement | positioning of the support pin in the direct type light source device used in the Example.
　以下に図面等を参照して説明を行うが、本願発明は図面の実施形態にのみ限定されるものではない。本明細書における第一の光学シートとは、光源から液晶パネル側の方向に対して、一番目に配置する光学シートをいい、第二以降の光学シートはそれぞれ、二番目、三番目、四番目と配置する順番の光学シートのことを示す（図１参照）。また、前面パネルに最も近い光学シートとは図１においては符合６の第四の光学シートが該当する。これらの光学シートはその設置の目的（例えば輝度向上）を阻害要因（例えば著しい厚みの増加、コストの上昇）が生じる事なく達成することが可能であれば、配置枚数の上限はない。 Hereinafter, the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments of the drawings. In the present specification, the first optical sheet refers to an optical sheet arranged first in the direction from the light source to the liquid crystal panel, and the second and subsequent optical sheets are the second, third, and fourth, respectively. And the optical sheets in the order of arrangement (see FIG. 1). Further, the optical sheet closest to the front panel corresponds to the fourth optical sheet denoted by reference numeral 6 in FIG. If these optical sheets can achieve the purpose of installation (for example, improvement in luminance) without causing any hindrance (for example, significant increase in thickness and cost), there is no upper limit on the number of sheets.
　先ず本発明に係る光学シートの表面形状など物理的構成につき説明した上で、続いて化学組成、他のシートの組合せ方法、装置構成などにつき説明する。 First, the physical configuration such as the surface shape of the optical sheet according to the present invention will be described, and then the chemical composition, the method of combining other sheets, the apparatus configuration, etc. will be described.
　１．本発明の光学シートの表面形状
　本発明の光学シートは、表面に直線畝状に形成された凸状のレンズ群を有する光学シートであって、該レンズ群の長さ方向に対する垂直断面形状における全てのレンズの凸状部外周線が、曲線および／または直線で構成され、かつ、前記曲線上の全ての点における接線および／または前記直線と基底線のなす角度（θ）がθ≧４０°である部分（Ｘ1）と、前記曲線上の全ての点における接線および／または前記直線と基底線のなす角度（θ）が２５°≦θ≦３５°である部分（Ｘ2）を含み、前記部分（Ｘ1）の前記レンズ群の基底線に投影した長さ（ｘ1）の総計（ｘ1total）が、前記レンズ群の基底線の長さの総計（Ｐtotal）の２５％以上６０％以下であり、かつ、前記部分（Ｘ2）の該レンズ群の基底線に投影した長さ（ｘ2）の総計（ｘ2total）が、前記レンズ群の基底線の長さの総計（Ｐtotal）の２５％以上６０％以下であることを特徴とする。 1. Surface shape of the optical sheet of the present invention The optical sheet of the present invention is an optical sheet having a convex lens group formed on the surface in a linear bowl shape, all in a vertical cross-sectional shape with respect to the length direction of the lens group. The outer peripheral line of the convex portion of the lens is composed of a curve and / or a straight line, and the tangent and / or the angle (θ) between the straight line and the base line at all points on the curve is θ ≧ 40 °. that an element (X 1), includes a portion (X 2) the angle of the tangent line and / or the straight line and the baseline (theta) is 25 ° ≦ θ ≦ 35 ° at all points on the curve, the The total length (x 1total ) of the length (x 1 ) projected onto the base line of the lens group of the portion (X 1 ) is 25% or more and 60% of the total length (P total ) of the base line length of the lens group. less and, and, on the baseline of the lens group of the partial (X 2) The length and shadow (x 2) total (x 2total), characterized in that the total length of the lens group of the base line is 60% or less 25% or more (P total).
　前記総計（ｘ1total）および総計（ｘ2total）を上記範囲とすることにより、光源からの光を冷陰極管列の中間部分へも充分に拡散でき、しかも中間部分における視野角方向への輝度を向上させることができる。さらに、視野角方向の輝度を上げるために、本発明の光学シートに、一般的に用いられるプリズムシートやレンズ付拡散シートなどの光学シートを重ね合わせた際にも、冷陰極管上領域の輝度が充分確保できる。 By setting the total (x 1total ) and the total (x 2total ) within the above range, the light from the light source can be sufficiently diffused into the intermediate portion of the cold cathode tube array, and the luminance in the viewing angle direction at the intermediate portion can be increased. Can be improved. Furthermore, in order to increase the luminance in the viewing angle direction, the luminance of the upper region of the cold cathode tube is also increased when an optical sheet such as a commonly used prism sheet or a diffusion sheet with a lens is superimposed on the optical sheet of the present invention. Can be secured sufficiently.
　なお、本発明でいう直線とは、その末端同士を結ぶまっすぐな線分のことをいうが、末端部分を結ぶ線分がほぼ直線に近い極小さな曲率をもつ曲線も含まれる。また、本発明でいう曲線とは、直線とは異なるが、直線に近い小さな曲率をもつ曲線も含まれる。本発明で規定する最小の構造単位はミクロンオーダーであるが、ミクロンオーダーで観察した場合、例えば電子顕微鏡などで光学シートの垂直断面を観察した場合などに、本発明で規定している曲線部分がそのオーダーで曲線と判断することが難しいような小さな曲率の曲線である場合、その判断は例えば、次のように行う。曲線上の２点を最短距離で結ぶ長さＡの直線に対して、その直線から最も離れた曲線上の点と直線の最短距離ｄとしたとき、１００×ｄ／Ａの値が１を超える場合は曲線と判断し、１００×ｄ／Ａの値が１以下の場合は直線と判断する。 In addition, although the straight line as used in the field of this invention means the straight line segment which connects the terminal ends, the curve in which the line segment which connects a terminal part has a very small curvature near a straight line is also contained. The curve referred to in the present invention includes a curve that is different from a straight line but has a small curvature close to the straight line. The minimum structural unit defined in the present invention is in the order of microns, but when observed in the order of microns, for example, when a vertical section of an optical sheet is observed with an electron microscope, the curved portion defined in the present invention is In the case of a curve with a small curvature that is difficult to determine as a curve in that order, the determination is performed as follows, for example. For a straight line of length A connecting two points on the curve with the shortest distance, the value of 100 × d / A exceeds 1 when the shortest distance d between the point on the curve farthest from the straight line and the straight line In this case, it is determined as a curve, and when the value of 100 × d / A is 1 or less, it is determined as a straight line.
　また、本発明において、最低部とは、単位レンズの凸状部外周線の最低点である。基底線とは、前記最低部と最低部とを結ぶ直線である。頂部とは、単位レンズの凸状部外周線において、基底線からの最高点である。 In the present invention, the lowest part is the lowest point of the outer peripheral line of the convex part of the unit lens. The base line is a straight line connecting the lowest part and the lowest part. The top portion is the highest point from the base line in the outer peripheral line of the convex portion of the unit lens.
　前記部分（Ｘ1）は、前記曲線上の全ての点における接線および／または前記直線と基底線のなす角度（θ）がθ≧４０°である。前記部分（Ｘ1）としては、例えば、後述する第１単位レンズの曲線部（Ｒ11）、第２単位レンズの曲線部（Ｒ21）、形状２を有する単位レンズの曲線部（Ｒ31）が該当する。すなわち、前記長さ（ｘ1）としては、例えば、後述する第１単位レンズの前記部分（Ｘ1）を基底線に投影した長さの総計（ｒ11）、第２単位レンズの前記部分（Ｘ1）を基底線に投影した長さの総計（ｒ21）、形状２を有する単位レンズの前記部分（Ｘ1）を基底線に投影した長さの総計（ｒ31）が該当する。 In the portion (X 1 ), an angle (θ) formed between a tangent line at all points on the curve and / or the straight line and a base line is θ ≧ 40 °. Examples of the portion (X 1 ) include a curved portion (R 11 ) of the first unit lens, a curved portion (R 21 ) of the second unit lens, and a curved portion (R 31 ) of the unit lens having the shape 2 described later. Is applicable. That is, as the length (x 1 ), for example, the total length (r 11 ) obtained by projecting the portion (X 1 ) of the first unit lens, which will be described later, onto the base line, and the portion of the second unit lens ( X 1) total length of the projected to the ground line (r 21), total of said portion (X 1) a length obtained by projecting the baseline of the unit lens having the shape 2 (r 31) corresponds.
　前記部分（Ｘ2）は、前記曲線上の全ての点における接線および／または前記直線と基底線のなす角度（θ）が２５°≦θ≦３５°である。前記部分（Ｘ2）としては、例えば、後述する第１単位レンズの曲線部（Ｒ12）、第２単位レンズの直線部（Ｒ22）、形状１を有する単位レンズの部分（Ｒ32）、形状２を有する単位レンズの部分（Ｒ34）が該当する。すなわち、前記長さ（ｘ2）としては、例えば、後述する第１単位レンズの前記部分（Ｘ2）を基底線に投影した長さの総計（ｒ12）、第２単位レンズの前記部分（Ｘ2）を基底線に投影した長さの総計（ｒ22）、形状１を有する単位レンズの前記部分（Ｘ2）を基底線に投影した長さの総計（ｒ32）、形状２を有する単位レンズの前記部分（Ｘ2）を基底線に投影した長さの総計（ｒ34）が該当する。 In the portion (X 2 ), an angle (θ) formed between a tangent line at all points on the curve and / or the straight line and a base line is 25 ° ≦ θ ≦ 35 °. Examples of the portion (X 2 ) include a curved portion (R 12 ) of the first unit lens described later, a straight portion (R 22 ) of the second unit lens, a portion of the unit lens (R 32 ) having the shape 1, The unit lens portion (R 34 ) having the shape 2 is applicable. That is, as the length (x 2 ), for example, the total length (r 12 ) obtained by projecting the portion (X 2 ) of the first unit lens, which will be described later, onto the base line, the portion of the second unit lens ( X 2) total length of the projected to the ground line (r 22), total of said portion (X 2) the length projected onto the baseline of the unit lens having a shape 1 (r 32), has a shape 2 This corresponds to the total length (r 34 ) obtained by projecting the portion (X 2 ) of the unit lens onto the base line.
　また、本発明の光学シートでは、表面に形成された凸状レンズ群の全てのレンズにおける部分（Ｘ1）および部分（Ｘ2）について、前記レンズ群の基底線に投影した長さを求める。従って、前記総計（ｘ1total）および前記総計（ｘ2total）には、後述する第１単位レンズ、第２単位レンズ、形状１を有する単位レンズおよび形状２を有する単位レンズだけでなく、他の構造を有する単位レンズ（例えば、レンチキュラー形状）も考慮される。つまり、後述する第二の実施形態であれば、図２に示すように、第２単位レンズとレンチキュラー形状の単位レンズについての総計を求めることとなる。 In the optical sheet of the present invention, the length projected on the base line of the lens group is obtained for the part (X 1 ) and the part (X 2 ) of all the lenses of the convex lens group formed on the surface. Accordingly, the total (x 1total ) and the total (x 2total ) include not only a first unit lens, a second unit lens, a unit lens having shape 1 and a unit lens having shape 2 which will be described later, but also other structures. Also considered are unit lenses having a lenticular shape (eg, lenticular shape). That is, in the second embodiment to be described later, as shown in FIG. 2, the total of the second unit lens and the lenticular unit lens is obtained.
　本発明の光学シートではこれらの表面形状は出光面側に設定される。一方、本発明の光学シートの入光面側の表面形状構成は特に制限はなく、平面、エンボス面、マット面、レンズなどの光学要素を持つ面などの中から適宜選択可能であるが、傷付防止、音鳴り防止、光散乱効果発揮などの観点から、エンボス面、マット面が好ましく用いられる。 In the optical sheet of the present invention, these surface shapes are set on the light exit surface side. On the other hand, the surface shape configuration on the light incident surface side of the optical sheet of the present invention is not particularly limited and can be appropriately selected from flat surfaces, embossed surfaces, mat surfaces, surfaces having optical elements such as lenses, etc. An embossed surface and a mat surface are preferably used from the viewpoints of preventing sticking, preventing sound noise, and exhibiting a light scattering effect.
　２．第一の実施態様および第二の実施態様
　第一および第二の実施態様を説明するために、光学シートに直線畝状に配されているレンズの直線畝方向（レンズの長さ方向）に対して直角の断面（垂直断面の形状）を利用して説明する（図４、図５参照）。本発明の第一の実施態様の光学シートは、前記レンズ群が、第１単位レンズ（図６参照）を有している。本発明の第二の実施態様の光学シートは、前記レンズ群が、第２単位レンズ（図７～図１０参照）を有している。 2. First Embodiment and Second Embodiment In order to explain the first and second embodiments, with respect to the linear wrinkle direction (lens length direction) of the lenses arranged in a straight wrinkle shape on the optical sheet This will be explained using a right-angled section (vertical section shape) (see FIGS. 4 and 5). In the optical sheet according to the first embodiment of the present invention, the lens group includes a first unit lens (see FIG. 6). In the optical sheet according to the second embodiment of the present invention, the lens group includes a second unit lens (see FIGS. 7 to 10).
　２－１．第１単位レンズ
　前記第１単位レンズは、単位レンズの長さ方向に対する垂直断面形状における凸状部外周線が曲線を主体に構成され、かつ、前記曲線上の全ての点における接線と基底線のなす角度（θ11）がθ11≧４０°である曲線部（Ｒ11）と、その曲線上の全ての点における接線と基底線のなす角度（θ12）が２５°≦θ12≦３５°である曲線部（Ｒ12）を含み、前記曲線部（Ｒ11）の該単位レンズ形状の基底線に投影した長さの総計（ｒ11）の前記基底線の全長に対する割合が２５％以上６０％以下であり、かつ、前記曲線部（Ｒ12）の該単位レンズ形状の基底線に投影した長さの総計（ｒ12）の前記基底線の全長に対する割合が２５％以上６０％以下である。 2-1. First unit lens In the first unit lens, a convex portion outer peripheral line in a vertical cross-sectional shape with respect to the length direction of the unit lens is mainly composed of a curve, and tangent lines and base lines of all points on the curve are formed. angle (theta 11) is the theta 11 ≧ 40 ° curved section and (R 11), the angle between the tangent and the base line at all points on the curve (theta 12) is 25 ° ≦ θ 12 ≦ 35 ° curved portion is comprises (R 12), wherein the curved portion (R 11) said unit said fraction of the total length of the base line of the lens total length of the projected the baseline configuration (r 11) is 25% or more 60 % And the ratio of the total length (r 12 ) of the curved portion (R 12 ) projected onto the base line of the unit lens shape to the total length of the base line is 25% or more and 60% or less. .
　前記曲線部（Ｒ11）の基底線に投影した長さの総計（ｒ11）の基底線全長に対する割合を２５％以上６０％以下とし、かつ、前記曲線部（Ｒ12）の基底線に投影した長さの総計（ｒ12）の基底線全長に対する割合を２５％以上６０％以下とすることにより、光源からの光を冷陰極管列の中間部分へも充分に拡散でき、しかも中間部分における視野角方向への輝度を向上させることができる。さらに、視野角方向の輝度を上げるために、本発明の光学シートに、一般的に用いられるプリズムシートやレンズ付拡散シートなどの光学シートを重ね合わせた際にも、冷陰極管上領域の輝度が充分確保できる。よって、第一の実施態様の光学シートを用いることにより、一層の薄肉化に伴う線光源と光学シートとの距離の近接化や、液晶表示装置の消費エネルギー削減やコスト低減のための線光源数の削減による線光源間隔の拡大という、ますます輝度ムラ解消が困難になってきた液晶表示パネルにおいても、輝度ムラの解消を実現することが可能となった。 The ratio of the total length (r 11 ) projected onto the base line of the curved portion (R 11 ) to the total length of the base line is 25% or more and 60% or less, and is projected onto the base line of the curved portion (R 12 ). By making the ratio of the total length (r 12 ) of the total length (r 12 ) to 25% or more and 60% or less, the light from the light source can be sufficiently diffused into the middle part of the cold cathode tube array, and in the middle part The luminance in the viewing angle direction can be improved. Furthermore, in order to increase the luminance in the viewing angle direction, the luminance of the upper region of the cold cathode tube is also increased when an optical sheet such as a commonly used prism sheet or a diffusion sheet with a lens is superimposed on the optical sheet of the present invention. Can be secured sufficiently. Therefore, by using the optical sheet of the first embodiment, the distance between the line light source and the optical sheet due to further thinning, the number of line light sources for reducing the energy consumption and cost of the liquid crystal display device It has become possible to eliminate uneven brightness even in liquid crystal display panels, where it has become increasingly difficult to eliminate uneven brightness, which is an increase in the interval between line light sources due to the reduction in the number of lines.
　２－１－１．曲線部
　前記曲線部（Ｒ11）は、設計容易性、加工性、光学性能の観点から、二次曲線の一部であることが好ましい。また、曲線部（Ｒ11）は、１つまたは２つ以上の二次曲線の組合せでもよく、凸状部外周線の左右に対称に配置されても、非対称に配置されてもよい。なお、二次曲線とは円も含む楕円、双曲線、放物線を意味する。前記曲線部（Ｒ11）が楕円の一部である場合、その離心率は、０．５０以上０．９５以下が好ましく、０．７０以上０．９３以下がさらに好ましく、０．８０以上０．９０以下がより好ましい。 2-1-1. Curve part The curve part (R 11 ) is preferably a part of a quadratic curve from the viewpoints of design easiness, workability, and optical performance. Further, the curved portion (R 11 ) may be a combination of one or two or more quadratic curves, and may be arranged symmetrically on the right and left of the convex portion outer peripheral line or asymmetrically arranged. The quadratic curve means an ellipse including a circle, a hyperbola, and a parabola. When the curved portion (R 11 ) is a part of an ellipse, the eccentricity is preferably 0.50 or more and 0.95 or less, more preferably 0.70 or more and 0.93 or less, and 0.80 or more and 0.8. 90 or less is more preferable.
　前記曲線部（Ｒ12）は、曲線部（Ｒ11）と同様、二次曲線の一部であってもよい。しかし、曲線部（Ｒ12）は、曲線上の全ての点における接線と基底線となす角度（θ12）が、２５°≦θ12≦３５°という狭い接線角度でありながら、しかも、基底線に投影した長さの総計（ｒ12）の基底線全長に対する割合が２５％以上６０％以下の長さを有する必要があることから、必ずしも二次曲線の一部である必要性はなく、上記の条件を満足する任意の１つまたは２つ以上の曲線で構成されてよい。しかも前記曲線部（Ｒ11）と同様に、凸状部外周線の左右に対称に配置されても、非対称に配置されてもよい。 The curved part (R 12 ) may be a part of a quadratic curve, like the curved part (R 11 ). However, the curve portion (R 12 ) has a narrow tangent angle of 25 ° ≦ θ 12 ≦ 35 ° (θ 12 ) between the tangent line and the base line at all points on the curve, and the base line. Since the ratio of the total projected length (r 12 ) to the total length of the base line needs to be 25% or more and 60% or less, it is not necessarily a part of the quadratic curve. It may be composed of any one or more curves that satisfy the following conditions. Moreover Like the curved portion (R 11), be arranged symmetrically to the right and left of the convex portion outer peripheral line may be arranged asymmetrically.
　前記第１単位レンズの長さ方向に対する垂直断面形状における凸状部外周線上の曲線は、前記曲線部（Ｒ11）と前記曲線部（Ｒ12）を含む２種類以上のセグメントから構成されるが、そのうち曲線部（Ｒ11）の基底線に投影した長さの総計（ｒ11）の基底線全長に対する割合は２５％以上６０％以下である。総計（ｒ11）の割合が２５％未満であると、冷陰極管列の中間部分への光拡散が減少するとともに、中間部分における視野角方向の輝度が低下して、輝度ムラを解消しにくくなる。一方、総計（ｒ11）の割合が６０％を超えると、視野角方向の輝度を上げるために一般的に用いられるプリズムシートやレンズ付拡散シートなどの光学シートを重ね合わせた際に、冷陰極管上領域の輝度が低下してしまい、新たな輝度ムラを引き起こしてしまう。総計（ｒ11）の割合は、より好ましくは２７％以上５８％以下であり、さらに好ましくは３０％以上５５％以下である。 The curve on the outer periphery of the convex portion in the vertical cross-sectional shape with respect to the length direction of the first unit lens is composed of two or more types of segments including the curved portion (R 11 ) and the curved portion (R 12 ). Of these, the ratio of the total length (r 11 ) projected onto the base line of the curved portion (R 11 ) to the total length of the base line is 25% or more and 60% or less. When the ratio of the total (r 11 ) is less than 25%, the light diffusion to the intermediate portion of the cold cathode tube array is reduced, and the luminance in the viewing angle direction at the intermediate portion is lowered, so that it is difficult to eliminate luminance unevenness. Become. On the other hand, when the ratio of the total (r 11 ) exceeds 60%, a cold cathode is formed when an optical sheet such as a prism sheet or a diffusion sheet with a lens generally used for increasing the luminance in the viewing angle direction is overlaid. The brightness of the tube upper area is lowered, causing new brightness unevenness. The ratio of the total (r 11 ) is more preferably 27% or more and 58% or less, and further preferably 30% or more and 55% or less.
　また、前記曲線部（Ｒ12）の基底線に投影した長さの総計（ｒ12）の基底線全長に対する割合は２５％以上６０％以下である。総計（ｒ12）の割合が２５％未満であると、視野角方向の輝度を上げるために、一般的に用いられるプリズムシートやレンズ付拡散シートなどの光学シートを重ね合わせた際に、冷陰極管上領域の輝度が低下してしまい、輝度ムラの解消が困難となる。一方、総計（ｒ12）の割合が６０％を超えると、冷陰極管列の中間部分への光拡散が減少するとともに、中間部分における視野角方向の輝度が低下して、輝度ムラを解消しにくくなる。総計（ｒ12）の割合は、より好ましくは２７％以上５８％以下であり、さらに好ましくは３０％以上５５％以下である。 Further, the ratio of the total length (r 12 ) projected onto the base line of the curved portion (R 12 ) to the total length of the base line is 25% or more and 60% or less. When the ratio of the total (r 12 ) is less than 25%, in order to increase the luminance in the viewing angle direction, when a commonly used optical sheet such as a prism sheet or a diffusion sheet with a lens is superposed, a cold cathode The luminance of the tube upper area is lowered, and it becomes difficult to eliminate luminance unevenness. On the other hand, if the ratio of the total (r 12 ) exceeds 60%, the light diffusion to the intermediate portion of the cold cathode tube array is reduced, and the luminance in the viewing angle direction at the intermediate portion is reduced, thereby eliminating the luminance unevenness. It becomes difficult. The ratio of the total (r 12 ) is more preferably 27% or more and 58% or less, and further preferably 30% or more and 55% or less.
　これら２種類の曲線部（Ｒ11、Ｒ12）は、直接連結して凸状部外周線を形成してもよく、あるいは直線部や、その曲線上の点における接線と基底線とのなす角度（θ13）が、３５°＜θ13＜４０°、またはθ13＜２５°の曲線部（Ｒ13）を介して連結されてもよい。ただし、本発明の目的である輝度の均整化を高めるためには、これらの接合部の基底線に投影した総計長さ（ｒ13）の基底線全長に対する割合は４０％以下であることが好ましく、２０％以下がより好ましい。 These two types of curved portions (R 11 , R 12 ) may be directly connected to form a convex portion outer peripheral line, or an angle formed by a tangent and a base line at a straight line portion or a point on the curve. (Θ 13 ) may be connected via a curved portion (R 13 ) of 35 ° <θ 13 <40 ° or θ 13 <25 °. However, in order to improve the luminance leveling that is the object of the present invention, the ratio of the total length (r 13 ) projected onto the base line of these joints to the total base line length is preferably 40% or less. 20% or less is more preferable.
　また、前記曲線部（Ｒ11）と前記曲線部（Ｒ12）との連結方法は、凸状部外周線の左右対称であっても、左右非対称であってもよく、これらの連結方法を調整することにより、より高度な輝度ムラ解消が可能となる。前記曲線部（Ｒ11）および前記曲線部（Ｒ12）の存在数は、上記ｒ11、ｒ12の割合を満足する限り、特に限定されないが、それぞれ２つずつ存在することが好ましい。前記曲線部（Ｒ11）と前記曲線部（Ｒ12）との設定位置は、どちらが基底部に近くても良い。前記曲線部（Ｒ11）が基底部に近いと成形性の点から望ましい。前記曲線部（Ｒ11）が基底部に近く、前記曲線部（Ｒ11）および曲線部（Ｒ12）が単位レンズの中心線を境に対称の位置になっていると成形性の観点から好ましい。 Further, the connecting method of the curved portion (R 11 ) and the curved portion (R 12 ) may be symmetrical with respect to the outer peripheral line of the convex portion or may be asymmetrical with the left and right sides, and these connecting methods are adjusted. By doing so, it is possible to eliminate more uneven brightness. The number of the curved portion (R 11 ) and the curved portion (R 12 ) is not particularly limited as long as the ratio of r 11 and r 12 is satisfied, but it is preferable that two exist each. Either of the setting positions of the curved portion (R 11 ) and the curved portion (R 12 ) may be close to the base portion. It is desirable from the viewpoint of moldability that the curved portion (R 11 ) is close to the base portion. From the viewpoint of moldability, it is preferable that the curved portion (R 11 ) is close to the base portion, and the curved portion (R 11 ) and the curved portion (R 12 ) are symmetric with respect to the center line of the unit lens. .
　２－２．第２単位レンズ
　前記第２単位レンズは、単位レンズの長さ方向に対する垂直断面形状における凸状部外周線が２つ以上の曲線と１つ以上の直線が連結した形状から構成され、かつ、前記曲線の少なくとも２つが、その曲線上の全ての点における接線と基底線のなす角度（θ21）がθ21≧４０°である曲線部（Ｒ21）を含み、前記直線（Ｒ22）と基底線のなす角度（θ22）が２５°≦θ22≦３５°である。 2-2. Second unit lens The second unit lens is formed of a shape in which a convex outer peripheral line in a vertical cross-sectional shape with respect to the length direction of the unit lens is formed by connecting two or more curves and one or more straight lines, and At least two of the curves include a curved portion (R 21 ) in which an angle (θ 21 ) between a tangent line and a base line at all points on the curve is θ 21 ≧ 40 °, and the straight line (R 22 ) and the base The angle (θ 22 ) between the lines is 25 ° ≦ θ 22 ≦ 35 °.
　垂直断面における凸状部外周線の直線、曲線の数、位置、曲線のθ21、直線のθ22を設定することにより、光源装置の冷陰極管直上近傍領域における視野角方向での輝度と、隣り合う冷陰極管の中間領域における視野角方向での輝度を各々独立して調整することが可能となる。よって、様々な装置設定（光源装置条件、本発明以外の光学シートとの組合せ）において光源装置面全体の高輝度均整度が実現できる。 By setting the straight line of the outer periphery of the convex portion in the vertical section, the number of curves, the position, θ 21 of the curve, θ 22 of the straight line, the luminance in the viewing angle direction in the region immediately above the cold cathode tube of the light source device, It is possible to independently adjust the luminance in the viewing angle direction in the intermediate region between adjacent cold-cathode tubes. Therefore, high brightness uniformity of the entire surface of the light source device can be realized in various device settings (light source device conditions, combinations with optical sheets other than the present invention).
　前記２つ以上の曲線と１つ以上の直線とは、例えば、図７～図１０に示すような断面の凸状部外周線をもつ単位レンズ構造である。直線の数はレンズ賦型に用いる母型の製造しやすさ、光学シート全体としての光学性能調整の容易さなどの観点から、好ましくは２つ以上である。 The two or more curves and the one or more straight lines are, for example, a unit lens structure having a convex portion outer peripheral line having a cross section as shown in FIGS. The number of straight lines is preferably two or more from the viewpoints of easy manufacture of a matrix used for lens shaping, ease of adjustment of optical performance as the entire optical sheet, and the like.
　２－２－１．曲線部
　前記第２単位レンズの凸状外周線を構成する曲線は、設計容易性、加工性、光学性能の観点から、楕円（円を含む）等の二次曲線の一部であることが好ましく、１つまたは２つ以上の二次曲線の組合せでもよい。前記第２単位レンズの長さ方向に対する垂直断面形状における凸状部外周線上の曲線が楕円（円を含む）を含む場合、その離心率は、０．５０以上０．９５以下が好ましく、０．７０以上０．９３以下がさらに好ましく、０．８０以上０．９０以下がより好ましい。 2-2-1. Curve part The curve constituting the convex outer peripheral line of the second unit lens is preferably a part of a quadratic curve such as an ellipse (including a circle) from the viewpoint of ease of design, workability, and optical performance. It may be a combination of one or more quadratic curves. When the curve on the outer peripheral line of the convex portion in the vertical cross-sectional shape with respect to the length direction of the second unit lens includes an ellipse (including a circle), the eccentricity is preferably 0.50 or more and 0.95 or less. 70 or more and 0.93 or less are more preferable, and 0.80 or more and 0.90 or less are more preferable.
　前記第２単位レンズの長さ方向に対する垂直断面形状における凸状部外周線上の曲線は、その曲線上の全ての点における接線と基底線のなす角度（θ21）がθ21≧４０°である曲線部（Ｒ21）を含む。ここで、前記曲線部（Ｒ21）の基底線に投影した長さの総計（ｒ21）の基底線全長に対する割合は２５％以上６０％以下が好ましい。総計（ｒ21）の割合が２５％未満であると、冷陰極管列の中間部分への光拡散が減少するとともに、中間部分における視野角方向の輝度が低下して、輝度ムラを解消しにくくなる。一方、総計（ｒ21）の割合が６０％を超えると、視野角方向の輝度を上げるために一般的に用いられるプリズムシートやレンズ付拡散シートなどの光学シートを重ね合わせた際に、冷陰極管上領域の輝度が低下してしまい、新たな輝度ムラを引き起こしてしまう。総計（ｒ21）の割合は、より好ましくは２７％以上５８％以下であり、さらに好ましくは３０％以上５５％以下である。 In the curve on the outer periphery of the convex portion in the vertical cross-sectional shape with respect to the length direction of the second unit lens, the angle (θ 21 ) between the tangent line and the base line at all points on the curve is θ 21 ≧ 40 °. Including the curved portion (R 21 ). Here, the ratio of the total length (r 21 ) projected on the base line of the curved portion (R 21 ) to the total length of the base line is preferably 25% or more and 60% or less. If the ratio of the total (r 21 ) is less than 25%, the light diffusion to the intermediate portion of the cold cathode tube array is reduced, and the luminance in the viewing angle direction at the intermediate portion is reduced, making it difficult to eliminate luminance unevenness. Become. On the other hand, when the ratio of the total (r 21 ) exceeds 60%, a cold cathode is formed when an optical sheet such as a prism sheet or a diffusion sheet with a lens generally used for increasing the luminance in the viewing angle direction is overlaid. The brightness of the tube upper area is lowered, causing new brightness unevenness. The ratio of the total (r 21 ) is more preferably 27% or more and 58% or less, and further preferably 30% or more and 55% or less.
　また、前記第２単位レンズの長さ方向に対する垂直断面形状における凸状部外周線上の曲線は、その曲線上の全ての点における接線と基底線のなす角度（θ23）が２５°≦θ23≦３５°である曲線部（Ｒ23）を含んでいてもよい。 Further, the curve on the outer peripheral line of the convex portion in the vertical cross-sectional shape with respect to the length direction of the second unit lens has an angle (θ 23 ) between the tangent line and the base line at all points on the curve of 25 ° ≦ θ 23. A curved portion (R 23 ) that is ≦ 35 ° may be included.
　２－２－２．直線部
　前記直線（Ｒ22）と基底線のなす角度（θ22）は２５°以上３５°以下の範囲に入っていなければならない。直線が２つ以上ある場合は、少なくとも１つ以上の角度（θ22）がこの範囲を満足していなければならない。また、角度（θ22）がこの範囲に入っていれば、各直線部の角度は異なっていてもよい。 2-2-2. Linear portion said linear angle (theta 22) of (R 22) and baseline must be within the range of less than 35 ° 25 ° or more. When there are two or more straight lines, at least one angle (θ 22 ) must satisfy this range. Further, as long as the angle (θ 22 ) is within this range, the angle of each straight line portion may be different.
　前記角度（θ22）をこれらの範囲に調整することで、単位レンズ全体、光学シート全体として平面が形成され、この平面の形成により、光源装置の冷陰極管直上近傍領域における視野角方向での輝度を向上させることが可能となり、通常のレンズシート（プリズムシート、レンチキュラーシート等）の設置により発生する光源装置の冷陰極管直上近傍領域における視野角方向での輝度低下を解消できる。 By adjusting the angle (θ 22 ) within these ranges, a plane is formed as the entire unit lens and the entire optical sheet. By forming this plane, the viewing angle direction in the region immediately above the cold cathode tube of the light source device The luminance can be improved, and a decrease in luminance in the viewing angle direction in the region near the cold cathode tube of the light source device, which is generated by installing a normal lens sheet (prism sheet, lenticular sheet, etc.) can be eliminated.
　また、様々な隣り合う冷陰極管同士の距離や本発明の光学シートと冷陰極管の距離の設定においても、前記角度（θ22）の設定を調整することにより、光源装置の冷陰極管直上近傍領域における視野角方向での輝度を向上させることが可能となる。また、本発明の光学シートと他の光学シートの組合せにおいても同様に、角度（θ22）の設定を調整する事により、光源装置の冷陰極管直上近傍領域における視野角方向での輝度を向上させることが可能となる。角度（θ22）がこの範囲入っていないと、光源装置の冷陰極管直上近傍領域の輝度を向上させることが困難となる。 Further, also in the setting of the distance between various adjacent cold cathode tubes and the distance between the optical sheet of the present invention and the cold cathode tube, the setting of the angle (θ 22 ) is adjusted so that it is directly above the cold cathode tube of the light source device. The luminance in the viewing angle direction in the vicinity region can be improved. Similarly, in the combination of the optical sheet of the present invention and other optical sheets, the brightness in the viewing angle direction in the region immediately above the cold cathode tube of the light source device is improved by adjusting the setting of the angle (θ 22 ). It becomes possible to make it. If the angle (θ 22 ) is not within this range, it will be difficult to improve the luminance in the region immediately above the cold cathode tube of the light source device.
　２－２－３．曲線と直線との組合せ
　第２単位レンズの凸状部外周線全体の形状は、前記した曲線と直線の設定の組合せから構成される。これらの組合せのうち、第２単位レンズの凸状部外周線の頂部の形状は、曲線部（例えば、図７～図９参照）であってもよく、直線部のみからなるいわゆるプリズム形状（例えば、図１０参照）であってもよく、また曲線部と直線部が結合した形状であってもよい。また、基底線と接する部分は直線、曲線のいずれでもよい。 2-2-3. Combination of curve and straight line The shape of the entire outer periphery of the convex portion of the second unit lens is composed of a combination of the curve and the straight line. Of these combinations, the shape of the top of the outer peripheral line of the convex portion of the second unit lens may be a curved portion (see, for example, FIGS. 7 to 9), or a so-called prism shape (for example, only a straight portion) 10), or a shape in which a curved portion and a straight portion are combined. Further, the portion in contact with the base line may be either a straight line or a curved line.
　曲線と直線の設定についての組合せの例を挙げると、図７は、断面形状における頂部の曲線を含む凸状部の３つの曲線が、単一の楕円形状を有するものである。図８は、２つの曲線と１つの直線からなり、この２つの曲線が単一の楕円形状を有するものである。図９は、断面形状における凸状部の曲線のうち、頂部と基底線と接する部分とが異なる楕円形状を有している例である。図１０は、断面形状の凸状部の頂部が二つの直線を組み合わせたプリズム形状を有している例である。 Referring to an example of a combination for setting a curve and a straight line, FIG. 7 shows that the three curves of the convex portion including the top curve in the cross-sectional shape have a single elliptical shape. FIG. 8 includes two curves and one straight line, and these two curves have a single elliptical shape. FIG. 9 is an example in which the apex and the portion in contact with the base line have different elliptical shapes in the convex curve in the cross-sectional shape. FIG. 10 is an example in which the top of the convex portion having a cross-sectional shape has a prism shape in which two straight lines are combined.
　曲線と直線の設定の配分は、凸状部外周線の曲線をレンズ形状の基底線に投影した長さの総計Ｖと、直線をレンズ形状の基底線に投影した長さの総計Ｗの割合で規定される。前記割合（Ｖ：Ｗ）は、１５：８５以上８５：１５以下となることが好ましい。この範囲において、様々な装置設定（光源装置条件、本発明以外の光学シートとの組合せ）に基づき、割合を調整することで、その設定における測定すべき（本発明の効果を発揮すべき）出光面側からみて、光源装置の隣り合う冷陰極管の中間領域における視野角方向での輝度を向上させ、かつ、冷陰極管直上近傍領域における視野角方向での輝度を向上させることが可能となり、光源装置面全体としての高輝度均整度が図れるのである。 The distribution of the setting of the curve and the straight line is a ratio of the total length V of the convex portion outer peripheral line projected onto the lens-shaped base line and the total length W of the straight line projected onto the lens-shaped base line. It is prescribed. The ratio (V: W) is preferably 15:85 or more and 85:15 or less. In this range, by adjusting the ratio based on various device settings (light source device conditions, combinations with optical sheets other than the present invention), light emission that should be measured in that setting (the effect of the present invention should be exhibited) From the surface side, it is possible to improve the luminance in the viewing angle direction in the intermediate region of the adjacent cold cathode tubes of the light source device, and improve the luminance in the viewing angle direction in the region immediately above the cold cathode tube, The high brightness uniformity as the whole surface of the light source device can be achieved.
　例えば、本発明の光学シートを第一光学シートとし、併用する第二光学シートをプリズムシートとした場合は、プリズムシートの頂角、ピッチにより最適な曲線と直線の割合を決定できる。その場合、前記割合（Ｖ：Ｗ）は、好ましくは２０：８０以上８０：２０以下であり、より好ましい割合は３０：７０以上８０：２０以下であり、さらに好ましい割合は４０：６０以上８０：２０以下である。曲線の割合がこれより小さくなると、冷陰極管配列の中間領域へ均一に充分な光を拡散できなくなり、これ以上大きくなると、プリズムシートを重ね合わせた際に発生する暗線の消去が困難となる。 For example, when the optical sheet of the present invention is a first optical sheet and the second optical sheet to be used together is a prism sheet, the optimal curve and straight line ratio can be determined by the apex angle and pitch of the prism sheet. In that case, the ratio (V: W) is preferably 20:80 or more and 80:20 or less, more preferably 30:70 or more and 80:20 or less, and further preferably 40:60 or more and 80:20 or less. 20 or less. If the ratio of the curve is smaller than this, sufficient light cannot be uniformly diffused to the intermediate region of the cold cathode tube array, and if it is larger than this, it becomes difficult to eliminate the dark line generated when the prism sheets are overlapped.
２－３．曲線の接線が基底線となす角
　前記第１および第２単位レンズの長さ方向に対する垂直断面形状において、凸状部外周線上の曲線の接線が基底線となす角のうち最大のものをθ11ｍａｘ、θ21ｍａｘとしたとき、これらのθ11ｍａｘ、θ21ｍａｘは、好ましくは４５°以上、より好ましくは５０°以上、更に好ましくは５５°以上である。 2-3. The angle formed by the tangent of the curve and the base line In the vertical cross-sectional shape with respect to the length direction of the first and second unit lenses, the maximum angle among the angles formed by the tangent of the curve on the outer periphery of the convex portion and the base line is θ 11. Assuming that max and θ 21 max, these θ 11 max and θ 21 max are preferably 45 ° or more, more preferably 50 ° or more, and further preferably 55 ° or more.
　一方、角度θ11、θ21が７５°以上となると、その曲線部分においては光源からの入射光が反射により、ほとんど正面方向へ出光できない。そのため、単位レンズ垂直断面形状の凸状部外周線上において、曲線部の接線が基底線となす角度θ11、θ21が７５°以上となる部分の基底線に投影した長さの総計は、基底線全長に対して１０％以下であることが好ましく、５％以下であることがより好ましい。角度θ11、θ21をこれらの範囲に調整することで、光源装置の隣り合う冷陰極管列の中間領域における視野角方向での輝度を向上させることが可能となる。 On the other hand, when the angles θ 11 and θ 21 are 75 ° or more, incident light from the light source hardly reflects in the front direction at the curved portion due to reflection. Therefore, the total length projected on the base line of the portion where the angle θ 11 , θ 21 is 75 ° or more on the outer peripheral line of the convex portion of the unit lens vertical cross-sectional shape and the base line is 75 ° It is preferably 10% or less, more preferably 5% or less, relative to the total length of the line. By adjusting the angles θ 11 and θ 21 within these ranges, it is possible to improve the luminance in the viewing angle direction in the intermediate region of the adjacent cold cathode tube rows of the light source device.
　また、様々な隣り合う冷陰極管列間隔の距離や本発明の光学シートと冷陰極管の距離の設定においても、条件を満たす２つ以上のθ11ｍａｘ、θ21ｍａｘの設定を調整する事により、隣り合う冷陰極管の中間領域における視野角方向での輝度を向上させることが可能となる。また、本発明の光学シートと他の光学シートの組合せにおいても同様に、条件を満たす２つ以上のθ11ｍａｘ、θ21ｍａｘの設定を調整する事により、隣り合う冷陰極管の中間領域における視野角方向での輝度を向上させることが可能となるため、光学シート全体として輝度ムラが低減できる。 Also, in the setting of various distances between adjacent cold-cathode tube rows and the distance between the optical sheet of the present invention and the cold-cathode tube, the setting of two or more θ 11 max and θ 21 max satisfying the conditions should be adjusted. Thus, it is possible to improve the luminance in the viewing angle direction in the intermediate region between adjacent cold-cathode tubes. Similarly, in the combination of the optical sheet of the present invention and another optical sheet, by adjusting the setting of two or more θ 11 max and θ 21 max satisfying the condition, in the intermediate region between adjacent cold cathode tubes. Since it becomes possible to improve the brightness | luminance in a viewing angle direction, a brightness nonuniformity can be reduced as the whole optical sheet.
　２－４．高さＨと幅Ｐの比率
　前記第１または第２単位レンズにおいて、単位レンズの長さ方向に対する垂直断面形状における基底線の長さ（Ｐ）と基底線からレンズ頂点までの高さ（Ｈ）の割合（Ｈ／Ｐ）は、特に限定はされないが、０．２５以上０．７５以下であることが好ましく、０．３以上０．６以下がより好ましい。前記第１単位レンズにおいては、前記割合（Ｈ／Ｐ）が上記範囲未満であると、曲線部（Ｒ11）の曲線部（Ｒ12）に対する構成割合が少なくなり、隣り合う冷陰極管の中間領域に充分に光を拡散させることが困難となり、この領域における視野角方向での輝度向上ができなくなる。一方、前記割合（Ｈ／Ｐ）が上記範囲を超えた場合、曲線部（Ｒ12）の曲線部（Ｒ11）に対する割合が小さくなり、プリズムシートやレンズ付拡散シートなどの光学シートを重ね合わせた際に、冷陰極管上領域の輝度が不足し、輝度ムラの解消が困難となる。また、前記第２単位レンズにおいては、前記割合（Ｈ／Ｐ）が上記範囲未満であると、レンズの効果が小さくなり、隣り合う冷陰極管の中間領域に充分に光を拡散させることが困難となり、この領域における視野角方向での輝度向上ができない。一方、前記割合（Ｈ／Ｐ）が上記範囲を超えた場合、隣り合う冷陰極管の中間領域を超えた部分まで光を拡散させてしまうため、中間領域で輝度均一性が低下してしまい、この領域における視野角方向での輝度均整度が低下する。なお、単位レンズの長さ（Ｐ）および高さ（Ｈ）は、所望とする特性に応じて適宜設定すればよいが、通常は長さ（Ｐ）は１０μｍ以上３００μｍ以下、高さ（Ｈ）は２．５μｍ以上２２５μｍ以下である。 2-4. Ratio of height H to width P In the first or second unit lens, the length (P) of the base line and the height (H) from the base line to the lens apex in the vertical sectional shape with respect to the length direction of the unit lens The ratio (H / P) is not particularly limited, but is preferably 0.25 or more and 0.75 or less, and more preferably 0.3 or more and 0.6 or less. In the first unit lens, when the ratio (H / P) is less than the above range, the composition ratio of the curved portion (R 11 ) to the curved portion (R 12 ) is reduced, and the middle of adjacent cold cathode tubes is reduced. It becomes difficult to sufficiently diffuse light into the region, and luminance in the viewing angle direction in this region cannot be improved. On the other hand, when the ratio (H / P) exceeds the above range, the ratio of the curved portion (R 12 ) to the curved portion (R 11 ) decreases, and an optical sheet such as a prism sheet or a diffusion sheet with a lens is overlaid. In this case, the luminance of the upper area of the cold cathode tube is insufficient, and it becomes difficult to eliminate the luminance unevenness. Further, in the second unit lens, when the ratio (H / P) is less than the above range, the effect of the lens is reduced, and it is difficult to sufficiently diffuse light to an intermediate region between adjacent cold cathode tubes. Therefore, the luminance cannot be improved in the viewing angle direction in this region. On the other hand, when the ratio (H / P) exceeds the above range, the light is diffused to a portion beyond the intermediate region of the adjacent cold cathode fluorescent lamps, resulting in a decrease in luminance uniformity in the intermediate region. The luminance uniformity in the viewing angle direction in this region is reduced. The length (P) and height (H) of the unit lens may be set as appropriate according to the desired characteristics. Usually, the length (P) is 10 μm or more and 300 μm or less, and the height (H). Is 2.5 μm or more and 225 μm or less.
　２－５．単位レンズ構造の組合せ
　前記第１または第２単位レンズ構造は、高輝度均整度を達成する為に最適の形状である。従って通常は、他の単位レンズ構造が入っていてもよい。光学シート全体として好ましい性能を発揮する為には、光学シートの出光面全体の５０面積％以上が第１単位レンズおよび／または第２単位レンズで構成されることが好ましく、６０面積％以上の構成がより好ましく、７０面積％以上の構成がさらに好ましく、９０面積％以上の構成がより好ましい。前記他のレンズ構造としては、例えばレンチキュラー形状やプリズム形状が挙げられる。これらの光学シートの単位レンズ構造構成において、第１または第２単位レンズ構造内訳は、同一のものの組合せ構成であっても、複数種類の構造のものの組合せ構成であっても構わない。なお、前記レンズ群が、前記第１または第２単位レンズのみで構成されていることも好ましい態様である。 2-5. Combination of unit lens structures The first or second unit lens structure has an optimum shape in order to achieve high brightness uniformity. Therefore, usually other unit lens structures may be included. In order to exhibit preferable performance as the entire optical sheet, it is preferable that 50% by area or more of the entire light exit surface of the optical sheet is configured by the first unit lens and / or the second unit lens, and the structure by 60% by area or more. Is more preferable, 70% by area or more is more preferable, and 90% by area or more is more preferable. Examples of the other lens structure include a lenticular shape and a prism shape. In the unit lens structure configuration of these optical sheets, the first or second unit lens structure breakdown may be a combination configuration of the same or a combination configuration of a plurality of types of structures. In addition, it is a preferable aspect that the lens group includes only the first or second unit lens.
　３．第三の実施態様
　第三の実施態様を説明するために、光学シートに直線畝状に配されているレンズの直線畝方向（レンズの長さ方向）に対して直角の断面（垂直断面の形状）を利用して説明する（図１１参照）。本発明の第三の実施態様の光学シートは、前記レンズ群が、長さ方向に対する垂直断面形状の凸状部外周線として、下記の形状１を有する単位レンズ（図１２参照）および形状２を有する単位レンズ（図１３参照）を有している。 3. Third Embodiment In order to explain the third embodiment, a cross-section (vertical cross-sectional shape) perpendicular to the straight wrinkle direction (lens length direction) of the lens arranged in a straight wrinkle shape on the optical sheet ) (See FIG. 11). In the optical sheet of the third embodiment of the present invention, the lens group includes a unit lens (see FIG. 12) and a shape 2 having the following shape 1 as a convex portion outer peripheral line having a vertical cross-sectional shape with respect to the length direction. It has a unit lens (see FIG. 13).
　このように、少なくとも２種類の異なる該単位レンズを略平行に配置させることにより、光学シートのレンズ賦型面全体としての表面形状が構成される。異なる２種類の該単位レンズの配置については、規則性なくランダムに配置してもよいし、一定の規則性をもって配置してもよい。 As described above, the surface shape of the entire lens shaping surface of the optical sheet is configured by arranging at least two different types of unit lenses substantially in parallel. The arrangement of the two different types of unit lenses may be arranged randomly without regularity, or may be arranged with a certain regularity.
　３－１．形状１
　前記形状１は、外周線が曲線または直線からなり、かつ、その曲線上の全ての点における接線または直線と該単位レンズ断面形状の基底線がなす角度（θ32）が２５°≦θ32≦３５°である部分（Ｒ32）を含み、前記部分（Ｒ32）の該単位レンズ断面形状の基底線に投影した長さの総計（ｒ32）が、該単位レンズ断面形状の基底線全長に対して９０％以上である。 3-1. Shape 1
In the shape 1, the outer peripheral line is a curve or a straight line, and the angle (θ 32 ) between the tangent line or the straight line at all points on the curve and the base line of the unit lens cross-sectional shape is 25 ° ≦ θ 32 ≦ includes a portion (R 32) is 35 °, the portion (R 32) the unit lens section total length of the projected the baseline of shape (r 32) is, the baseline full length of the unit lens cross section On the other hand, it is 90% or more.
　前記形状１は、その曲線上の全ての点における接線または直線と基底線とのなす角度（θ32）が、２５°≦θ32≦３５°となる部分（Ｒ32）を含むが、このＲ32の基底線に投影した長さの総計（ｒ32）の基底線全長に対する割合は９０％以上である。前記総計（ｒ32）の割合が９０％未満であると、視野角方向の輝度を上げるために一般的に用いられるプリズムシートやレンズ付拡散シートなどの光学シートを重ね合わせた際に、冷陰極管上領域の輝度が低下してしまい、輝度ムラの解消が困難となる。前記総計（ｒ32）の割合は、より好ましくは９５％以上であり、さらに好ましくは１００％である。また、前記形状１の９０％以上を占める部分（Ｒ32）は、直線または曲線からなり、複数の直線、曲線の組み合わせでも良い。例えば、二つの直線からなるいわゆるプリズム形状は、本発明の好ましい態様の一つである。また、曲線を含む場合は、該曲線は、設計容易性、加工性、光学性能の観点から、二次曲線の一部であることが好ましく、なかでも双曲線の一部であることがより好ましい。また、形状１は左右非対称の形状であってもよいが、視野角による輝度ムラ差を小さくするために左右対称であることが好ましい。 The shape 1 includes a portion (R 32 ) where an angle (θ 32 ) between a tangent or straight line and a base line at all points on the curve is 25 ° ≦ θ 32 ≦ 35 °. The ratio of the total length (r 32 ) projected onto 32 baselines to the total baseline is 90% or more. When the ratio of the total (r 32 ) is less than 90%, a cold cathode is formed when an optical sheet such as a prism sheet or a diffusion sheet with a lens generally used for increasing the luminance in the viewing angle direction is overlaid. The luminance of the tube upper area is lowered, and it becomes difficult to eliminate luminance unevenness. The ratio of the total (r 32 ) is more preferably 95% or more, and further preferably 100%. Further, the portion (R 32 ) occupying 90% or more of the shape 1 is composed of a straight line or a curve, and may be a combination of a plurality of straight lines and curves. For example, a so-called prism shape composed of two straight lines is one of the preferred embodiments of the present invention. When a curve is included, the curve is preferably a part of a quadratic curve, more preferably a part of a hyperbola from the viewpoints of design easiness, workability, and optical performance. The shape 1 may be a left-right asymmetric shape, but is preferably left-right symmetric in order to reduce the luminance unevenness difference due to the viewing angle.
　３－２．形状２
　前記形状２は、外周線が曲線部を主体に構成され、かつ、単一の二次曲線で表される部分（Ｒ33）の該単位レンズ形状の基底線に投影した長さの総計（ｒ33）が、該単位レンズ形状の基底線全長に対して９０％以上であり、かつ前記部分（Ｒ33）の一部として、その曲線上の全ての点における接線と基底線のなす角度（θ31）が、θ31≧４０°である曲線部（Ｒ31）を含み、前記部分（Ｒ31）の該レンズ断面形状の基底線に投影した長さの総計（ｒ31）の基底線全長に対する割合が２０％以上である。 3-2. Shape 2
The shape 2 is a total of the lengths (r) projected on the base line of the unit lens shape of a portion (R 33 ) whose outer peripheral line is mainly composed of a curved portion and represented by a single quadratic curve. 33 ) is 90% or more with respect to the total length of the base line of the unit lens shape, and, as a part of the portion (R 33 ), an angle (θ between the tangent line and the base line at all points on the curve. 31), the curved portion is theta 31 ≧ 40 ° comprises a (R 31), relative to baseline length of said portion (the lens section total length of the projected the baseline of the shape of the R 31) (r 31) The ratio is 20% or more.
　前記形状２は、単一の二次曲線で表される部分（Ｒ33）を有するが、この二次曲線としては楕円または双曲線の一部であることが好ましい。部分（Ｒ33）が楕円の一部である場合、その離心率は、０．５０以上０．９５以下が好ましく、０．７０以上０．９３以下がさらに好ましく、０．８０以上０．９０以下がより好ましい。また、上記形状２には、その曲線上の全ての点における接線と基底線とのなす角度（θ31）が、θ31≧４０°である曲線部（Ｒ31）を含むが、この曲線部（Ｒ31）の基底線に投影した長さの総計（ｒ31）の基底線全長に対する割合は２０％以上である。総計（ｒ31）の割合が２０％未満であると、冷陰極管列の中間部分への光拡散が減少するとともに、中間部分における視野角方向の輝度が低下して、輝度ムラを解消しにくくなる。また形状２は左右非対称の形状であってもよいが、視野角による輝度ムラ差を小さくするために左右対称であることが好ましい。 The shape 2 has a portion (R 33 ) represented by a single quadratic curve, and the quadratic curve is preferably an ellipse or a part of a hyperbola. When the portion (R 33 ) is a part of an ellipse, the eccentricity is preferably 0.50 or more and 0.95 or less, more preferably 0.70 or more and 0.93 or less, and 0.80 or more and 0.90 or less. Is more preferable. The shape 2 includes a curved portion (R 31 ) where the angle (θ 31 ) between the tangent line and the base line at all points on the curve is θ 31 ≧ 40 °. The ratio of the total length (r 31 ) projected onto the baseline of (R 31 ) to the total length of the baseline is 20% or more. When the ratio of the total (r 31 ) is less than 20%, the light diffusion to the intermediate portion of the cold cathode tube array is reduced, and the luminance in the viewing angle direction at the intermediate portion is reduced, making it difficult to eliminate luminance unevenness. Become. The shape 2 may be an asymmetric shape, but is preferably left-right symmetric in order to reduce the luminance unevenness difference depending on the viewing angle.
　また、前記形状２は、通常、前記部分（Ｒ33）の一部として、その曲線上の全ての点における接線と基底線のなす角度（θ34）が、２５°≦θ34≦３５°である部分（Ｒ34）も有している。 In the shape 2, the angle (θ 34 ) between the tangent line and the base line at all points on the curve is usually 25 ° ≦ θ 34 ≦ 35 ° as a part of the portion (R 33 ). It also has a portion (R 34 ).
　３－３．形状１と形状２の組合せ
　第三の実施態様の光学シートにおける単位レンズの長さ方向に対する垂直断面形状としての形状１および形状２は、上述の条件を満たす形状であればそれぞれ単一の形状である必要はなく、形状１および形状２としてそれぞれ上述の条件を満たす複数種の形状が存在してもよい。 3-3. Combination of shape 1 and shape 2 Shape 1 and shape 2 as the vertical cross-sectional shape with respect to the length direction of the unit lens in the optical sheet of the third embodiment are each a single shape as long as the above conditions are satisfied. There is no need, and the shape 1 and the shape 2 may include a plurality of types that satisfy the above-described conditions.
　前記形状１を有する単位レンズと前記形状２を有する単位レンズは、出光面全体に対するそれぞれの投影面積の合計として、形状１を有する単位レンズと形状２を有する単位レンの面積比（形状１／形状２）が０．０５以上２．０以下となるように配置されることが好ましい。この面積比が０．０５未満であると視野角方向の輝度を上げるために、一般的に用いられるプリズムシートやレンズ付拡散シートなどの光学シートを重ね合わせた際に、冷陰極管上領域の輝度が低下してしまい、輝度ムラの解消が困難となるおそれがある。一方、前記面積比が２．０を超えると、冷陰極管列の中間部分への光拡散が減少するとともに、中間部分における視野角方向の輝度が低下して、輝度ムラを解消しにくくなる。前記面積比は、より好ましくは０．１以上１．５以下であり、さらに好ましくは０．１５以上１．０以下であり、最も好ましくは０．２以上０．７５以下である。 As for the unit lens having the shape 1 and the unit lens having the shape 2, the area ratio of the unit lens having the shape 1 and the unit lens having the shape 2 (shape 1 / shape) is the sum of the respective projection areas on the entire light exit surface. 2) is preferably arranged to be 0.05 or more and 2.0 or less. In order to increase the luminance in the viewing angle direction when the area ratio is less than 0.05, when an optical sheet such as a commonly used prism sheet or a diffusion sheet with a lens is overlapped, Luminance decreases, and it may be difficult to eliminate luminance unevenness. On the other hand, when the area ratio exceeds 2.0, the light diffusion to the intermediate portion of the cold cathode tube array is reduced, and the luminance in the viewing angle direction at the intermediate portion is lowered, making it difficult to eliminate luminance unevenness. The area ratio is more preferably 0.1 or more and 1.5 or less, further preferably 0.15 or more and 1.0 or less, and most preferably 0.2 or more and 0.75 or less.
　また、形状１および形状２の配置としては、上記面積比率を満たしながら、形状１、形状２に属するレンズ同士がそれぞれ連続的に隣り合うのは、２０本以下とすることが好ましく、１０本以下とすることがより好ましい。形状１、形状２に属するレンズ同士が上記範囲より多く連続的に隣り合った場合、光学シート全体としての光学性能の均一性が損なわれ、輝度均整化が不十分となるおそれがある。輝度均整化のためには、前記面積比(形状１／形状２）を満たしながら、全体として略均一に配置されることが好ましい。母型作成の観点からは、同一の配置パターンの繰返しが、作製が容易であり、光学シート全体の均一性も設計しやすく、最も好ましい。 In addition, as the arrangement of the shape 1 and the shape 2, it is preferable that the lenses belonging to the shape 1 and the shape 2 are successively adjacent to each other while satisfying the above-described area ratio, and preferably 20 or less. More preferably. When the lenses belonging to the shape 1 and the shape 2 are continuously adjacent to each other more than the above range, the uniformity of the optical performance of the entire optical sheet is impaired, and the luminance leveling may be insufficient. In order to level the luminance, it is preferable that the layers are arranged substantially uniformly as a whole while satisfying the area ratio (shape 1 / shape 2). From the viewpoint of creating a master mold, it is most preferable to repeat the same arrangement pattern because it is easy to produce and the uniformity of the entire optical sheet is easy to design.
　３－４．高さＨと幅Ｐの比率
　単位レンズの長さ方向に対する垂直断面形状における凸状部外周線の基底線の長さ（Ｐ）は、形状１を有する単位レンズの基底線の長さ（Ｌ１）および形状２を有する単位レンズの基底線の長さ（Ｌ２）ともに３０μｍ以上３００μｍ以下であることが好ましく、４０μｍ以上２００μｍ以下がより好ましく、５０μｍ以上１５０μｍ以下がさらに好ましい。長さ（Ｐ）が上記範囲を超えた場合、視野角方向での輝度均整度が低下したり、重ね合わせる光学シートとの組合せによってはモアレパターンが生じやすくなる傾向がある。一方、長さ（Ｐ）が上記範囲未満であると、第三の実施態様の光学シートを、レンズ形状に正対した母型を用いてレンズ形状を転写して製造する際に、レンズ形状転写後の離型が困難となるおそれがある。 3-4. Ratio of height H to width P The length (P) of the base line of the outer peripheral line of the convex portion in the vertical cross-sectional shape with respect to the length direction of the unit lens is the length (L1) of the base line of the unit lens having the shape 1 In addition, the length (L2) of the base line of the unit lens having the shape 2 is preferably 30 μm or more and 300 μm or less, more preferably 40 μm or more and 200 μm or less, and further preferably 50 μm or more and 150 μm or less. When the length (P) exceeds the above range, the luminance uniformity in the viewing angle direction tends to decrease, or a moire pattern tends to occur depending on the combination with the optical sheet to be superimposed. On the other hand, when the length (P) is less than the above range, when the optical sheet of the third embodiment is manufactured by transferring the lens shape using a matrix facing the lens shape, the lens shape transfer Later mold release may be difficult.
　また、単位レンズの長さ方向に対する垂直断面形状における凸状部外周線の基底線からレンズ頂点までの高さ（Ｈ）は、形状１を有する単位レンズの高さ（Ｈ１）および形状２を有する単位レンズの高さ（Ｈ２）ともに１５μｍ以上１００μｍ以下が好ましく、２０μｍ以上８５μｍ以上がさらに好ましく、２５μｍ以上６５μｍ以下がより好ましい。高さ（Ｈ）が上記範囲を超えた場合、第三の実施態様の光学シートを、レンズ形状に正対した母型を用いてレンズ形状を転写して製造する際に、レンズ形状転写後の離型が困難となるおそれがある。一方、高さ（Ｈ）が上記範囲未満であると、レンズの光拡散効果が小さくなり、輝度均整度が低下するおそれがある。 Further, the height (H) from the base line of the convex portion outer peripheral line to the lens apex in the vertical cross-sectional shape with respect to the length direction of the unit lens has the height (H1) of the unit lens having the shape 1 and the shape 2. The height (H2) of the unit lens is preferably 15 μm or more and 100 μm or less, more preferably 20 μm or more and 85 μm or more, and more preferably 25 μm or more and 65 μm or less. When the height (H) exceeds the above range, when the optical sheet of the third embodiment is manufactured by transferring the lens shape using a matrix facing the lens shape, after the lens shape transfer Release may be difficult. On the other hand, if the height (H) is less than the above range, the light diffusing effect of the lens is reduced, and the luminance uniformity may be reduced.
　上記高さ（Ｈ）と長さ（Ｐ）の割合（Ｈ／Ｐ）は、特に限定はされないが、形状１を有する単位レンズとしては、割合（Ｈ１／Ｌ１）が０．２０以上０．４０以下であることが好ましく、０．２２以上０．３５以下がより好ましい。一方、形状２を有する単位レンズとしては、割合（Ｈ２／Ｌ２）が０．２５以上０．７５以下であることが好ましく、０．３０以上０．６５以下がより好ましい。前記割合（Ｈ／Ｐ）が上記範囲未満であると、レンズの光拡散効果が小さくなり、輝度均整度が低下するおそれがある。一方、前記割合（Ｈ／Ｐ）が上記範囲を超えた場合、単位レンズで拡散した光が、隣り合う単位レンズへ再度入光し、前面パネル方向へ出光しないケースが増え、輝度が低下するおそれがある。 The ratio (H / P) between the height (H) and the length (P) is not particularly limited, but as a unit lens having the shape 1, the ratio (H1 / L1) is 0.20 or more and 0.40. Or less, more preferably 0.22 or more and 0.35 or less. On the other hand, as a unit lens having the shape 2, the ratio (H2 / L2) is preferably 0.25 or more and 0.75 or less, and more preferably 0.30 or more and 0.65 or less. When the ratio (H / P) is less than the above range, the light diffusing effect of the lens becomes small, and the luminance uniformity may be lowered. On the other hand, when the ratio (H / P) exceeds the above range, the light diffused by the unit lens may be incident on the adjacent unit lens again and may not be emitted toward the front panel, which may reduce the luminance. There is.
　３－５．単位レンズ構造の組合せ
　第三の実施形態の光学シートにおいて、形状１を有する単位レンズと形状２を有する単位レンズは、高輝度均整度を達成する為に最適の形状および組み合わせである。従って通常は、他の単位レンズ構造が入っていてもよい。光学シート全体として好ましい性能を発揮する為には、光学シートの出光面全体の８０面積％以上が、前記形状１を有する単位レンズおよび前記形状２を有する単位レンズで構成されることが好ましく、９０面積％以上の構成がさらに好ましく、９５面積％以上の構成がより好ましい。他の単位レンズ構造は、同一のものの組合せ構成であっても、複数のものの組合せ構成であっても構わない。 3-5. Combination of Unit Lens Structures In the optical sheet of the third embodiment, the unit lens having the shape 1 and the unit lens having the shape 2 are optimally shaped and combined to achieve high brightness uniformity. Therefore, usually other unit lens structures may be included. In order to exhibit preferable performance as the entire optical sheet, it is preferable that 80% by area or more of the entire light exit surface of the optical sheet is constituted by the unit lens having the shape 1 and the unit lens having the shape 2; A structure of area% or more is more preferable, and a structure of 95 area% or more is more preferable. The other unit lens structures may be the same combination or a plurality of combination structures.
　４．光学シート平面状の単位レンズの配置方法
　本発明の光学シートは単位レンズの長さ方向に対する垂直断面において、隣り合う単位レンズの凸状部外周線の頂部の間隔が、３００μｍ以下であることが好ましい。前記間隔が３００μｍを超えると、視野角方向での輝度均整度が低下したり、重ね合わせる光学シートとの組合せによってはモアレパターンが生じやすくなる。これら直線畝状に配置されるレンズ群の配置は、光学シート全体として、前記配置比率となっていればよい。例えば、前記第１もしくは第２単位レンズ、または、形状１を有する単位レンズおよび形状２を有する単位レンズが、上記間隔で並んでいてもよく、その他の単位レンズ（例えばレンチキュラー形状やプリズム形状）が隣であっても構わない。 4). Optical sheet planar unit lens arrangement method In the optical sheet of the present invention, in the vertical cross section of the unit lens in the length direction, the distance between the apexes of the convex portion outer peripheral lines of adjacent unit lenses is preferably 300 μm or less. . When the distance exceeds 300 μm, the luminance uniformity in the viewing angle direction is lowered, or a moire pattern is likely to occur depending on the combination with the optical sheet to be superimposed. The arrangement of the lens groups arranged in the shape of the straight saddles only needs to be the arrangement ratio of the entire optical sheet. For example, the first or second unit lens, or the unit lens having the shape 1 and the unit lens having the shape 2 may be arranged at the above intervals, and other unit lenses (for example, a lenticular shape or a prism shape) may be arranged. It may be next door.
　本発明の光学シートにおいて、隣り合う単位レンズ間の連結部の構成は目的とする光学性能に影響を与えなければ、特に制限がない。例えば、単位レンズの設計どおりの光学性能のみを光学シート全体で達成したい場合には、理想的には、単位レンズの長さ方向に対する垂直断面における凸状部外周線の最低部全てが基底線と一致していること、すなわち隙間なく単位レンズを配置することが好ましい。 In the optical sheet of the present invention, the configuration of the connecting portion between adjacent unit lenses is not particularly limited as long as the target optical performance is not affected. For example, when it is desired to achieve only the optical performance as designed for the unit lens with the entire optical sheet, ideally, the lowest part of the outer peripheral line of the convex part in the vertical cross section with respect to the length direction of the unit lens is the base line. It is preferable that the unit lenses are aligned, that is, the unit lenses are arranged without gaps.
　しかし、光学シート全体としての光学性能に影響を与えない範囲であれば、各単位レンズ間に隙間を設けてもよい。例えば、本発明の光学シートのレンズ形状を転写する工程においてレンズ形状転写後の離型が容易になるように、わずかな隙間を与えることなどがこれに当たる。このわずかな隙間により本発明の光学シートに与えられる単位レンズ間の断面形状については、直線、凹状の曲線、Ｖ字等どのような形状であっても、光学性能に影響を与えなければ、本発明では隙間がないことと同義である。 However, a gap may be provided between each unit lens as long as it does not affect the optical performance of the entire optical sheet. For example, in the step of transferring the lens shape of the optical sheet of the present invention, a slight gap is given so as to facilitate release after the lens shape transfer. With respect to the cross-sectional shape between the unit lenses given to the optical sheet of the present invention by this slight gap, any shape such as a straight line, a concave curve, or a V-shape can be used as long as the optical performance is not affected. The invention is synonymous with no gap.
　また、逆に本発明で規定する特定の形状を有する単位レンズの光学性能を補助したり、強めたり、他の光学性能を補ったりする為に、隣り合う単位レンズの最低部同士を離間させ、その間に目的に応じた効果を発現するような形状を加えても良い。 On the contrary, in order to assist the optical performance of the unit lens having a specific shape defined in the present invention, to strengthen, or to supplement other optical performance, the minimum unit of the adjacent unit lenses are separated from each other, In the meantime, a shape that exhibits an effect according to the purpose may be added.
　５．本発明の光学シートの構成
　５－１．透明性熱可塑性樹脂
　本発明の光学シートを構成する熱可塑性樹脂は、透明なものであり且つ光学シートの主な構成要素として適度な強度を有するものであれば特に制限されない。例えば、ポリカーボネート樹脂；ポリメチルメタクリレートなどのアクリル系樹脂；ポリスチレン、ポリビニルトルエン、ポリ（ｐ－メチルスチレン）などのスチレン系樹脂；ＭＳ樹脂（メチルメタクリレートとスチレンの共重合体）；ノルボルネン系樹脂などのポリオレフィン樹脂；ポリアリレート樹脂；ポリエーテルスルホン樹脂これらのうち２種以上の混合樹脂などを用いることができる。好適にはポリカーボネート樹脂、スチレン系樹脂またはノルボルネン系樹脂を用いる。中でもポリカーボネート樹脂は、透明性や耐熱性、加工性に優れており、且つそれらのバランスがよいので光学シート用の樹脂として特に好ましい。前記熱可塑性樹脂は、必要に応じて、紫外線吸収剤、蛍光増白剤、難燃剤などを含んでいてもよい。 5). Configuration of optical sheet of present invention 5-1. Transparent thermoplastic resin The thermoplastic resin constituting the optical sheet of the present invention is not particularly limited as long as it is transparent and has an appropriate strength as a main component of the optical sheet. For example, polycarbonate resin; acrylic resin such as polymethyl methacrylate; styrene resin such as polystyrene, polyvinyl toluene, poly (p-methylstyrene); MS resin (copolymer of methyl methacrylate and styrene); norbornene resin Polyolefin resin; Polyarylate resin; Polyethersulfone resin Among these, two or more kinds of mixed resins can be used. A polycarbonate resin, a styrene resin, or a norbornene resin is preferably used. Among these, polycarbonate resin is particularly preferable as a resin for an optical sheet because it is excellent in transparency, heat resistance, and workability and has a good balance. The thermoplastic resin may contain an ultraviolet absorber, a fluorescent whitening agent, a flame retardant, and the like as necessary.
　５－２．光拡散層
　本発明の光学シートは、透明樹脂のみで構成されていても良いが、光拡散性を調整する為に、光拡散能を有する粒子による光拡散層を設けても良い。光拡散層は、光学シート全体、レンズ部のみ、レンズ部以外全体、出光面表層のみ、入光面表層のみあるいは、中間層に均一、あるいはランダムに分散させてよい。光拡散層は、透明樹脂とは屈折率が０．０１以上の差を有する光拡散性粒子（光拡散剤）が、熱可塑性樹脂中に分散されているものであり、レンズによる光拡散の拡散方向や拡散割合などの調整効果を有しており、視野角方向での輝度均整度をより高めることを可能にする。ここで、光源装置に使用する光学シートの枚数を減らした場合、バックライトユニットにおいて光学シートを支えるピンのイメージが現れるという問題が生じることがある。しかし、本発明の光学シートにおいて、光拡散層を設けることにより、使用枚数を減らした場合でも、支持ピンイメージを消去することができる。 5-2. Light Diffusion Layer The optical sheet of the present invention may be composed only of a transparent resin, but in order to adjust light diffusibility, a light diffusion layer made of particles having light diffusibility may be provided. The light diffusing layer may be uniformly or randomly dispersed in the entire optical sheet, only the lens portion, the entire portion other than the lens portion, only the light exit surface layer, only the light entrance surface layer, or the intermediate layer. In the light diffusion layer, light diffusing particles (light diffusing agent) having a refractive index of 0.01 or more different from that of a transparent resin are dispersed in a thermoplastic resin. It has adjustment effects such as direction and diffusion ratio, and it is possible to further increase the brightness uniformity in the viewing angle direction. Here, when the number of optical sheets used in the light source device is reduced, there may be a problem that an image of pins supporting the optical sheet appears in the backlight unit. However, by providing the light diffusion layer in the optical sheet of the present invention, the support pin image can be erased even when the number of sheets used is reduced.
　５－３．光拡散剤
　光拡散性粒子（微粒子）の材質としては、例えば、（メタ）アクリル系樹脂、スチレン系樹脂、ポリウレタン系樹脂、ポリエステル系樹脂、シリコーン系樹脂、フッ素系樹脂、これらの共重合体などの合成樹脂；ガラス；スメクタイト、カオリナイトなどの粘土化合物；シリカ、アルミナなどの無機酸化物；などが挙げられる。これらの材質のうち、（メタ）アクリル系樹脂、シリコーン系樹脂、シリカが特に好適である。光拡散剤は、これら例示の材質の単一材料、単一材料の混合物、混合材料、混合材料の混合物のどれを用いてもかまわない。なお、本願において、（メタ）アクリルとは、アクリルおよび／またはメタクリルを意味する。 5-3. Light diffusing agent Examples of the material of the light diffusing particles (fine particles) include (meth) acrylic resins, styrene resins, polyurethane resins, polyester resins, silicone resins, fluororesins, and copolymers thereof. Glass; clay compounds such as smectite and kaolinite; inorganic oxides such as silica and alumina; and the like. Of these materials, (meth) acrylic resins, silicone resins, and silica are particularly suitable. The light diffusing agent may be a single material, a mixture of single materials, a mixed material, or a mixture of mixed materials of these exemplified materials. In the present application, (meth) acryl means acryl and / or methacryl.
　光拡散性粒子の平均粒子径は、０．１μｍ以上５０μｍ以下が好ましく、０．３μｍ以上１０μｍ以下がより好ましく、０．５μｍ以上５μｍ以下がさらに好ましい。光拡散性粒子の粒径が上記範囲を外れた場合、十分な光拡散性を発揮できないおそれがある。ここで、光拡散性粒子の平均粒子径とは、粒度分布測定装置（コールターカウンター）により測定される体積基準メディアン径である。 The average particle size of the light diffusing particles is preferably from 0.1 μm to 50 μm, more preferably from 0.3 μm to 10 μm, and even more preferably from 0.5 μm to 5 μm. When the particle size of the light diffusing particles is out of the above range, there is a possibility that sufficient light diffusing properties cannot be exhibited. Here, the average particle diameter of the light diffusing particles is a volume-based median diameter measured by a particle size distribution measuring device (Coulter counter).
　熱可塑性樹脂と光拡散性粒子との割合は、適宜調整すればよいが、例えば熱可塑性樹脂１００質量部に対して光拡散性粒子を０．０１質量部以上、１０質量部以下程度添加すればよい。光拡散性粒子が０．０１質量部未満であると、光拡散剤による輝度均整度調整が十分にできなくなる。一方、光拡散性粒子が１０質量部を超えると光拡散層の透明度が低下して光学シート全体の輝度が低下するおそれがあり得る。 The ratio between the thermoplastic resin and the light diffusing particles may be adjusted as appropriate. For example, if the light diffusing particles are added in an amount of 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin. Good. When the amount of the light diffusing particles is less than 0.01 parts by mass, the luminance uniformity adjustment by the light diffusing agent cannot be sufficiently performed. On the other hand, if the light diffusing particles exceed 10 parts by mass, the transparency of the light diffusing layer may be lowered, and the brightness of the entire optical sheet may be lowered.
　本発明の光学シートにおいて、光学性能として異方光拡散性能をより高める必要がある場合には、光学シートの成形時に異方光拡散性を発現できる低架橋密度有機微粒子が好ましく用いられる。前記低架橋密度有機微粒子の原料単量体としては、（メタ）アクリル酸、メチル（メタ）アクリレート、エチル（メタ）アクリレート、ｎ－プロピル（メタ）アクリレート、ｉｓｏ－プロピル（メタ）アクリレート、ｎ－ブチル（メタ）アクリレート、ｉｓｏ－ブチル（メタ）アクリレート、ｔ－ブチル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレート、シクロヘキシル（メタ）アクリレート、ベンジル（メタ）アクリレート、ヒドロキシエチル（メタ）アクリレート、ヒドロキシプロピル（メタ）アクリレートなどの（メタ）アクリレート類；スチレン、ｐ－メチルスチレン、ビニルトルエン、ｐ－ｔ－ブチルスチレンなどのスチレン類；Ｎ－フェニルマレイミド、Ｎ－シクロヘキシルマレイミド、Ｎ－ベンジルマレイミドなどのマレイミド類；（メタ）アクリルアミド、Ｎ－メチロール（メタ）アクリルアミドなどの（メタ）アクリルアミド類；（メタ）アクリロニトリルなどのアクリロニトリル類；Ｎ－ビニルピロリドン；の１種、或いはこれらのうち２種以上を混合して用いることができる。 In the optical sheet of the present invention, when it is necessary to further enhance the anisotropic light diffusion performance as the optical performance, low crosslink density organic fine particles capable of exhibiting anisotropic light diffusibility during the molding of the optical sheet are preferably used. Raw material monomers for the low crosslink density organic fine particles include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n- Butyl (meth) acrylate, iso-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxy (Meth) acrylates such as propyl (meth) acrylate; styrenes such as styrene, p-methylstyrene, vinyltoluene, pt-butylstyrene; N-phenylmaleimide, N-cyclohexylmaleimide, N-benzylmaleimi One or more of (meth) acrylamide, (meth) acrylamides such as N-methylol (meth) acrylamide; acrylonitriles such as (meth) acrylonitrile; N-vinylpyrrolidone; or two or more of these Can be mixed and used.
　低架橋密度有機微粒子の架橋剤としては、エチレングリコールジ（メタ）アクリレート、ジエチレングリコールジ（メタ）アクリレート、プロピレングリコールジ（メタ）アクリレート、ネオペンチルグリコールジ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート、ビスヒドロキシエチルビスフェノールＡジ（メタ）アクリレートなどの多官能（メタ）アクリレート；ジビニロキシエトキシ（メタ）アクリレート、ジアリルフタレート、アリル（メタ）アクリレート、ジビニルベンゼンなどのラジカル重合性架橋剤；ビスフェノールＡジグリシジルエーテル、ジエチレングリコールジグリシジルエーテル、ネオペンチルグリコールジグリシジルエーテルなどの多官能エポキシ化合物；トリレンジイソシアネート、キシリレンジイソシアネート、イソホロンジイソシアネートなどの多官能イソシアネート化合物；Ｎ－メチロールメラミン、Ｎ－メチロールベンゾグアナミンなどの多官能メチロール化合物；の１種、或いはこれらのうち２種以上を混合して用いることができる。 Low crosslinking density organic fine particle crosslinking agents include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and trimethylolpropane tri (meth). Polyfunctional (meth) acrylates such as acrylate and bishydroxyethyl bisphenol A di (meth) acrylate; radical polymerizable crosslinking agents such as divinyloxyethoxy (meth) acrylate, diallyl phthalate, allyl (meth) acrylate, and divinylbenzene; bisphenol Polyfunctional epoxy compounds such as A diglycidyl ether, diethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether; tolylene diisocyanate, Siri diisocyanate, polyfunctional isocyanate compounds such as isophorone diisocyanate; N- methylol melamine, polyfunctional methylol compounds such as N- methylol benzoguanamine; one, or may be used in combination of two or more thereof.
　異方光拡散性能を出す為の低架橋密度有機微粒子は、架橋密度が０．００１％以上、０．１２％以下であることが好ましい。このような低架橋密度の有機微粒子は、原料段階では球状または略球状であるが、光学シート成形時に受ける熱、せん断力などにより、光学シートの所定の位置（層など）で楕円体形状あるいは棒状を呈するようになり、この形状に変化することにより異方拡散性を発現する。なお、架橋密度とは、次式（１）で求められる数値のことである。 The crosslink density of the low crosslink density organic fine particles for achieving anisotropic light diffusion performance is preferably 0.001% or more and 0.12% or less. Such organic fine particles having a low cross-linking density are spherical or substantially spherical at the raw material stage, but are formed into an ellipsoidal shape or a rod shape at a predetermined position (layer, etc.) of the optical sheet due to heat, shearing force, etc. received during molding of the optical sheet. When this shape is changed, anisotropic diffusivity is expressed. In addition, a crosslinking density is a numerical value calculated | required by following Formula (1).
Figure JPOXMLDOC01-appb-M000001
　Ｆｎ（ｃ）：ラジカル重合体系架橋微粒子製造に用いる架橋剤の官能基数
　Ｍｗ（ｃ）：ラジカル重合体系架橋微粒子製造に用いる架橋剤の分子量
　Ｗ（ｃ）：ラジカル重合体系架橋微粒子製造に用いる架橋剤の質量配合割合（％）
　Ｗ（ｍ）：ラジカル重合体系架橋微粒子製造に用いる単量体の質量配合割合（％）
　ただし、Ｆｎ（ｃ）≧２、Ｗ（ｍ）＋Ｗ（ｃ）＝１００
Figure JPOXMLDOC01-appb-M000001
Fn (c): number of functional groups of the crosslinking agent used for producing the radical polymer-based crosslinked fine particles Mw (c): molecular weight of the crosslinking agent used for producing the radical polymer-based crosslinked fine particles W (c): crosslinking agent used for producing the radical polymer-based crosslinked fine particles Mass blending ratio (%)
W (m): Mass blending ratio (%) of monomer used for production of radical polymerized crosslinked fine particles
However, Fn (c) ≧ 2, W (m) + W (c) = 100
　５－４．酸化防止剤
　本発明の低架橋密度有機微粒子を含む有機微粒子、または熱可塑性樹脂の少なくとも一方に、さらに酸化防止剤を配合してもよい。酸化防止剤は加熱成形時における酸化や劣化による熱可塑性樹脂や有機微粒子の着色を抑制することができるので、本発明の光学シートを適用したバックライト装置の輝度をより確実に発揮せしめることができる。 5-4. Antioxidant An antioxidant may be further blended in at least one of the organic fine particles including the low crosslink density organic fine particles of the present invention or the thermoplastic resin. Since the antioxidant can suppress coloring of the thermoplastic resin and organic fine particles due to oxidation and deterioration during thermoforming, the brightness of the backlight device to which the optical sheet of the present invention is applied can be more reliably exhibited. .
　前記酸化防止剤としては従来公知のものを用いることができる。例えば、ペンタエリスリトールテトラキス［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］、オクタデシル－３－（３，５－ジ－ｔ－ブチル－１－ヒドロキシフェニル）プロピオネートなどのヒンダードフェノール系酸化防止剤；トリス（２，４－ジ－ｔ－ブチルフェニル）フォスファイト、トリス［２－［［２，４，８，１０－テトラ－ｔ－ブチルジベンゾ［ｄ，ｆ］［１，３，２］ジオキサフォスフェフィン－６－イル］オキシ］エチル］アミンなどのリン系酸化防止剤；芳香環を有するものとして、チオジエチレンビス［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］など、芳香環を有さないものとして、ペンタエリスリチルテトラキス（３－ラウリルチオプロピオネート）などの硫黄系酸化防止剤；３－ヒドロキシ－５，７－ジ－ｔ－ブチル－フラン－２－オンとｏ－キシレンの反応生成物などのラクトン系酸化防止剤；還元型牛脂を原料としたアルキルアミンの酸化生成物などのヒドロキシルアミン系酸化防止剤；３，４－ジヒドロ－２，５，７，８－テトラメチル－２－（４，８，１２－トリメチルトリデシル）－２Ｈ－ベンゾピラン－６－オールなどのビタミンＥ系酸化防止剤などを使用できる。 As the antioxidant, a conventionally known antioxidant can be used. For example, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-1-hydroxyphenyl) propionate, etc. Hindered phenolic antioxidants; tris (2,4-di-t-butylphenyl) phosphite, tris [2-[[2,4,8,10-tetra-t-butyldibenzo [d, f] [ Phosphorous antioxidants such as 1,3,2] dioxaphosphine-6-yl] oxy] ethyl] amine; thiodiethylenebis [3- (3,5-di-t -Butyl-4-hydroxyphenyl) propionate] and the like having no aromatic ring, pentaerythrityltetrakis (3-laurylthiopropionate) Sulfur-based antioxidants such as; lactone-based antioxidants such as the reaction product of 3-hydroxy-5,7-di-t-butyl-furan-2-one and o-xylene; Hydroxylamine antioxidants such as oxidation products of alkylamines; 3,4-dihydro-2,5,7,8-tetramethyl-2- (4,8,12-trimethyltridecyl) -2H-benzopyran- Vitamin E antioxidants such as 6-ol can be used.
　酸化防止剤の使用量は適宜調整すればよいが、通常、熱可塑性樹脂に対して０．００５質量％以上、０．３質量％以下程度添加すればよい。すなわち、熱可塑性樹脂１００質量部に対して酸化防止剤を０．００５質量部以上、０．３質量部以下程度添加すればよい。 The amount of the antioxidant used may be adjusted as appropriate, but it is usually sufficient to add about 0.005 mass% or more and 0.3 mass% or less with respect to the thermoplastic resin. That is, an antioxidant may be added in an amount of about 0.005 parts by mass to about 0.3 parts by mass with respect to 100 parts by mass of the thermoplastic resin.
　本発明の光学シートの厚さは適宜調整することができ、特に制限されないが、通常は０．３ｍｍ以上、１０ｍｍ以下程度とすることができる。光学シートの厚さが、０．３ｍｍ未満であると光拡散作用が十分に発揮できなかったり、剛性が不足して形状安定性が維持できない場合がある。一方、光学シートの厚さが１０ｍｍを超えると本発明の光学シートを適用した装置全体をコンパクトにできないおそれがあるからである。光学シートの厚さは、より好ましくは、０．５ｍｍ以上、５ｍｍ以下とする。なお、光学シートの厚さとは、基底部の厚さと単位レンズ高さの合計である（図４，５，１１参照）。 The thickness of the optical sheet of the present invention can be adjusted as appropriate and is not particularly limited, but can usually be about 0.3 mm or more and 10 mm or less. If the thickness of the optical sheet is less than 0.3 mm, the light diffusing action may not be sufficiently exhibited, or the rigidity may be insufficient to maintain the shape stability. On the other hand, if the thickness of the optical sheet exceeds 10 mm, the entire apparatus to which the optical sheet of the present invention is applied may not be made compact. More preferably, the thickness of the optical sheet is 0.5 mm or more and 5 mm or less. The thickness of the optical sheet is the sum of the thickness of the base and the unit lens height (see FIGS. 4, 5, and 11).
　６．光学シートの製造方法
　本発明の光学シートは、所定の表面形状に正対した母型を用いて製造することが出来る。母型の形状は、得られる光学シートのレンズ群が、本発明で規定する所定の表面形状を実現する為の形状、すなわち、これらの表面形状の凸の部分が凹に、凹の部分が凸になる構造であればよい。なお、本発明ではこれらの構造の母型のことを“表面形状を形成する為の正対する母型”（図１４、１５参照）とする。 6). Manufacturing method of optical sheet The optical sheet of the present invention can be manufactured by using a matrix facing a predetermined surface shape. The shape of the matrix is a shape for the lens group of the obtained optical sheet to realize the predetermined surface shape defined in the present invention, that is, the convex portion of these surface shapes is concave and the concave portion is convex. Any structure can be used. In the present invention, the matrix having these structures is referred to as a “facing matrix for forming the surface shape” (see FIGS. 14 and 15).
　本発明の光学シートは、前記母型を有する製造工程によって製造することが出来る。具体的には、透明熱可塑性樹脂、あるいは、透明熱可塑性樹脂に光拡散性を有する微粒子を配合させたものを用いて、公知の押出し成形や射出成形により得ることが出来る。光学性能やその他の物性を調整する為に積層体とする場合（例えば、光拡散層を入光側あるいはレンズ側といった特定の層にのみ設置する場合や、光学シートの耐光性向上のための紫外線吸収剤配合層や、静電気による光学シートへの粉塵付着を防止するための帯電防止層を設置する場合）には、押出し成形による方法が生産性の点から特に好ましい。また、特にピッチが狭いレンズ形状を賦型する際は、特願２００８－２４９２５４に記載の方法を用いるのが特に好ましい。 The optical sheet of the present invention can be manufactured by a manufacturing process having the matrix. Specifically, it can be obtained by known extrusion molding or injection molding using a transparent thermoplastic resin or a mixture of transparent thermoplastic resin and fine particles having light diffusibility. When a laminated body is used to adjust optical performance and other physical properties (for example, when a light diffusing layer is installed only on a specific layer such as a light incident side or a lens side, or UV light for improving the light resistance of an optical sheet) In the case of installing an absorber blending layer or an antistatic layer for preventing dust from adhering to the optical sheet due to static electricity), the extrusion method is particularly preferable from the viewpoint of productivity. Further, it is particularly preferable to use the method described in Japanese Patent Application No. 2008-249254 when shaping a lens shape having a narrow pitch.
　本発明の設計どおりの成型物が製造できているかどうかは、成型物から、ｘ１、ｘ２を求めることで確認できる。具体的には、単位レンズの長さ方向に対する垂直断面形状を電子顕微鏡等で撮影し、その凸状部外周線において、曲線部分については、該曲線に対して適度な曲線（複数の組み合わせでも良い）をフィッティングし、その接線が基底線となす角度が所定の角度となる外周線の範囲から求め、また、直線部分については、直線が基底線となる角度が所定の角度となす外周線の範囲から求める。 Whether or not a molded product according to the design of the present invention can be manufactured can be confirmed by obtaining x 1 and x 2 from the molded product. Specifically, a vertical cross-sectional shape with respect to the length direction of the unit lens is photographed with an electron microscope or the like, and an appropriate curve (a plurality of combinations may be used) with respect to the curved portion in the outer peripheral line of the convex portion. ) And the angle between the tangent line and the base line is determined from the range of the outer peripheral line, and for the straight line portion, the range of the outer peripheral line where the angle at which the straight line is the base line is the predetermined angle. Ask from.
　７．他の光学シートとの組合せ
　本発明の光学シートは、他の光学シート、装置設定において、その高い光学性能調整能力を効率よく用いるために、第一の光学シートとして用いることが好ましい。第一の光学シートとして用いることにより、光源装置の隣り合う冷陰極管の中間領域における視野角方向での輝度を向上させる効果と、冷陰極管直上近傍領域における視野角方向での輝度を向上させる効果が最大限に活用できる。また、第一の光学シートとして用いた場合、その他の光学シートとしては、プリズムシート、拡散シート、マイクロレンズシート等を用いることができ、その組合せも光源装置の条件等によって適した組合せを選択することができるが、このとき、前面パネルに最も近い光学シートとしては、拡散シートを用いることが好ましい。中でも第二以降の光学シートに、少なくとも１枚のプリズムシートを使用することにより更に冷陰極管上付近に発生する暗線を解消し、前面パネル直前の出光面において高輝度で輝度均整度を実現することが可能となる。 7). Combination with Other Optical Sheet The optical sheet of the present invention is preferably used as the first optical sheet in order to efficiently use its high optical performance adjustment capability in other optical sheets and apparatus settings. By using it as the first optical sheet, the effect of improving the luminance in the viewing angle direction in the intermediate region of the adjacent cold cathode tubes of the light source device and the luminance in the viewing angle direction in the region immediately above the cold cathode tube are improved. The effect can be utilized to the maximum. When used as the first optical sheet, the other optical sheet can be a prism sheet, a diffusion sheet, a microlens sheet, etc., and the combination is also selected according to the conditions of the light source device. At this time, it is preferable to use a diffusion sheet as the optical sheet closest to the front panel. In particular, the use of at least one prism sheet for the second and subsequent optical sheets eliminates dark lines generated near the cold cathode tube and achieves high brightness and brightness uniformity on the light exit surface immediately before the front panel. It becomes possible.
　また、さらなるコスト低減のため、光源装置に使用する光学シートの枚数を減らすことが求められている。ここで、光学シートの使用枚数を減らした場合、輝度ムラの解消がより困難になるだけでなく、バックライトユニットにおいて光学シートを支えるピンのイメージが現れるという問題が生じる。すなわち、従来の光学シートでは、線光源のパターンを消去するために多数（４枚以上）の光学シート群を必要としていたため、これらの光学シートの作用により支持ピンのイメージも消去されて、支持ピンイメージが問題となることはなかった。なお、従来の光学シートでは、使用枚数を３枚に減らした場合、線光源のパターンを消去できないため、支持ピンイメージを認識することはできなかった。 Also, for further cost reduction, it is required to reduce the number of optical sheets used in the light source device. Here, when the number of used optical sheets is reduced, not only is the luminance unevenness more difficult to be solved, but also there is a problem that an image of pins that support the optical sheet appears in the backlight unit. That is, in the conventional optical sheet, a large number (four or more) of optical sheet groups are required to erase the pattern of the line light source. Pin image was never a problem. In the conventional optical sheet, when the number of sheets used is reduced to 3, the pattern of the line light source cannot be erased, so that the support pin image cannot be recognized.
　しかし、本発明の光学シートでは、プリズムシートと併用することにより優れた光拡散性能を発現するため、光学シートの使用枚数を３枚に減らしても、線光源のパターンを消去することが可能となる。そこで、本発明の光学シートを用いて、使用枚数を３枚に減すことにより、初めて支持ピンのイメージが急激に目立ってくることが判明した。ここで、本発明の光学シートが光拡散層を有している場合には、直下型光源装置において、光学シートを支持する支持ピンのイメージを消去する性能も向上している。従って、本発明の光学シートが光拡散層を有している場合には、本発明の光学シート、プリズムシートおよび光拡散シートの３枚のみを用いることも好ましい態様である。 However, since the optical sheet of the present invention exhibits excellent light diffusion performance when used in combination with a prism sheet, the pattern of the line light source can be erased even if the number of optical sheets used is reduced to three. Become. Thus, it has been found that the image of the support pin becomes noticeable only for the first time by reducing the number of sheets used to 3 using the optical sheet of the present invention. Here, when the optical sheet of the present invention has a light diffusing layer, in the direct type light source device, the performance of erasing the image of the support pins that support the optical sheet is also improved. Accordingly, when the optical sheet of the present invention has a light diffusing layer, it is also a preferable aspect to use only three sheets of the optical sheet, the prism sheet and the light diffusing sheet of the present invention.
　本発明により製造される光学シートは、光を所望の方向に拡散させることができ、結果として光の均一性を保つことができるので、需要が高まっている液晶ディスプレイ装置の製造コストを低減しつつ高輝度を発揮できるものとして産業上極めて有用である。よって、本発明の光学シートおよび当該光学シートを有する直下型光源装置は、液晶ディスプレイ装置などへ適用することによりその製造コストを低減することができる。 The optical sheet manufactured according to the present invention can diffuse light in a desired direction, and as a result, can maintain the uniformity of the light, thereby reducing the manufacturing cost of the liquid crystal display device, which is in increasing demand. It is extremely useful industrially as a material that can exhibit high brightness. Therefore, the manufacturing cost can be reduced by applying the optical sheet of the present invention and the direct light source device having the optical sheet to a liquid crystal display device or the like.
　次に本発明の実施例としての実例を表１～６にあげ説明するが、本発明は本例に限定されることはない。 Next, actual examples as examples of the present invention will be described in Tables 1 to 6, but the present invention is not limited to these examples.
　１．光学シートの製造
　ポリカーボネートを原料として、押し出し成型により、入光面にエンボス加工（算術平均粗さＲａ＝２～６μｍ）、出光面に種々の断面形状を有する直線畝状レンズ群を配した光学シートを製造した。 1. Manufacture of optical sheet An optical sheet made of polycarbonate as a raw material by extrusion molding with an embossing (arithmetic mean roughness Ra = 2 to 6 μm) on the light incident surface and linear rod-shaped lens groups having various cross-sectional shapes on the light emitting surface. Manufactured.
　２．光学シートの表面測定
　製造した種々の光学シートの断面形状は、走査型電子顕微鏡を用いて確認をした。表面形状の観察結果は表１～３に示す。 2. Surface measurement of optical sheet The cross-sectional shapes of various optical sheets produced were confirmed using a scanning electron microscope. The observation results of the surface shape are shown in Tables 1 to 3.
　３．輝度ムラ評価
　試験には、内寸幅６９０ｍｍ、奥行き３９０ｍｍ、深さ１０ｍｍのプラスチックケースの内面に白色の反射板を備え、反射板の底から３．５ｍｍ離れた位置に、直径３ｍｍの冷陰極管１９本を２０．５ｍｍ間隔で平行に配置した直下型光源装置を用いた。直下型光源装置上に、各種形状の本発明の光学シートをレンズ加工面が上となり、かつレンズの長手方向が冷陰極管の長手方向と平行となるように配置した。この光学シートの上に、市販の光拡散シート（宏茂光電（蘇州）有限公司製　ＣＨ２７３）、プリズムシート（住友スリーエム製　ＢＥＦ　ＩＩ　９０／５０：頂角９０度、ピッチ５０μｍ）、マイクロレンズシート（宏茂光電（蘇州）有限公司製　ＭＬ２４Ｍ：片方の表面に半球状の凸レンズ群が細密に配置された光学シート）を表４に示す組み合わせのとおりにのせた。それぞれの組み合わせにおいて、直下型光源装置の中心から垂直方向に４００ｍｍ離れた位置から目視で輝度ムラを観察した。輝度ムラは１０段階で評価し、値の大きいものほど輝度ムラが少なく、冷陰極管のランプイメージが目立たなくなっていることを示す。評価結果は表１～３に示す。 3. For the luminance unevenness evaluation test, a white reflective plate is provided on the inner surface of a plastic case having an inner width of 690 mm, a depth of 390 mm, and a depth of 10 mm, and a cold cathode tube having a diameter of 3 mm at a position 3.5 mm away from the bottom of the reflector. A direct type light source device in which 19 pieces were arranged in parallel at intervals of 20.5 mm was used. On the direct type light source device, the optical sheets of the present invention having various shapes were arranged such that the lens processing surface was on top and the longitudinal direction of the lens was parallel to the longitudinal direction of the cold cathode tube. On this optical sheet, a commercially available light diffusing sheet (CH273 manufactured by Hiroshige Kogyo (Suzhou) Co., Ltd.), prism sheet (BEF II 90/50 manufactured by Sumitomo 3M: apex angle 90 degrees, pitch 50 μm), microlens sheet ( ML24M manufactured by Hiroshige Kogyo (Suzhou) Co., Ltd .: an optical sheet in which hemispherical convex lens groups are finely arranged on one surface) was placed according to the combinations shown in Table 4. In each combination, luminance unevenness was visually observed from a position 400 mm away from the center of the direct light source device in the vertical direction. The brightness unevenness is evaluated in 10 stages, and the larger the value, the less the brightness unevenness, indicating that the lamp image of the cold cathode tube is not noticeable. The evaluation results are shown in Tables 1 to 3.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　表１～３に記載の光学シートについて、レンズ群を構成する各単位レンズの長さ（ｘ1）、長さ（ｘ2）および、レンズ群全体での総計（ｘ1total）、総計（ｘ2total）を表５にまとめた。 For the optical sheets described in Tables 1 to 3, the length (x 1 ), length (x 2 ) of each unit lens constituting the lens group, and the total (x 1total ) and total (x 2total ) of the entire lens group Are summarized in Table 5.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　総計（ｘ1total）が、前記レンズ群の基底線の長さの総計（Ｐtotal）の２５％～６０％であり、かつ、総計（ｘ2Total）が、前記レンズ群の基底線の長さの総計（Ｐtotal）の２５％～６０％である実施例１～３５を用いた場合、表４に示すいずれの組合せにおいても、輝度ムラが少ない。 The total (x 1total ) is 25% to 60% of the total length (P total ) of the baseline of the lens group, and the total (x 2Total ) is the length of the baseline of the lens group When Examples 1 to 35 that are 25% to 60% of the total (P total ) are used, the luminance unevenness is small in any combination shown in Table 4.
　４．支持ピンイメージ、輝度ムラ評価
　試験には、内寸幅６９０ｍｍ、奥行き３９０ｍｍ、深さ２５ｍｍのプラスチックケースの内面に白色の反射板を備え、反射板の底から５ｍｍ離れた位置に、直径３ｍｍの冷陰極管８本を４５ｍｍ間隔で平行に配置し、図３０に示すとおり支持ピンを配置した直下型光源装置を用いた。直下型光源装置上に、各種形状の本発明の光学シートをレンズ加工面が上となり、かつレンズの長手方向が冷陰極管の長手方向と平行となるように配置した。この光学シートの上に、プリズムシート（住友スリーエム製　ＢＥＦ　ＩＩ　９０／５０：頂角９０度、ピッチ５０μｍ）をのせ、さらにその上にマイクロレンズシート（宏茂光電（蘇州）有限公司製　ＭＬ２４Ｍ：片方の表面に半球状の凸レンズ群が細密に配置された光学シート）をのせた。各光学シート群において、直下型光源装置の中心から垂直方向に４００ｍｍ離れた位置から目視で支持ピンイメージ、輝度ムラを観察した。支持ピンイメージは、目視にて確認できた場合を「不良」、一部確認できるものを「良」、全く確認できないものを「優」とした。輝度ムラは１０段階で評価し、値の大きいものほど輝度ムラが少なく、冷陰極管のランプイメージが目立たなくなっていることを示す。評価結果は表６に示す。 4). Support pin image, luminance unevenness evaluation For the test, a white reflective plate is provided on the inner surface of a plastic case with an inner dimension width of 690 mm, a depth of 390 mm, and a depth of 25 mm, and a cold 3 mm diameter is placed at a position 5 mm away from the bottom of the reflector. A direct type light source device in which eight cathode tubes were arranged in parallel at intervals of 45 mm and support pins were arranged as shown in FIG. 30 was used. On the direct type light source device, the optical sheets of the present invention having various shapes were arranged such that the lens processing surface was on top and the longitudinal direction of the lens was parallel to the longitudinal direction of the cold cathode tube. A prism sheet (BEF II 90/50: vertical angle 90 degrees, pitch 50 μm, manufactured by Sumitomo 3M) is placed on this optical sheet, and a microlens sheet (manufactured by Hiroshige Kogyo (Suzhou) Co., Ltd.) ML24M: one side An optical sheet in which hemispherical convex lens groups are finely arranged is placed on the surface. In each optical sheet group, the support pin image and the luminance unevenness were visually observed from a position 400 mm away from the center of the direct light source device in the vertical direction. As for the support pin image, when it was confirmed visually, it was judged as “bad”, when it was confirmed partially, “good”, and when it could not be confirmed at all, “excellent”. The brightness unevenness is evaluated in 10 stages, and the larger the value, the less the brightness unevenness, indicating that the lamp image of the cold cathode tube is not noticeable. The evaluation results are shown in Table 6.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　実施例１３は、総計（ｘ1Total）および総計（ｘ2Total）が本発明の規定範囲内であり、かつ、光拡散層を設けている光学シートである。この実施例１３の光学シートを用いた場合、３枚の光学シート群により支持ピンイメージを消去でき、かつ、輝度ムラが少ない。 Example 13 is an optical sheet in which the total (x 1Total ) and the total (x 2Total ) are within the specified range of the present invention, and a light diffusion layer is provided. When the optical sheet of Example 13 is used, the support pin image can be erased by the group of three optical sheets, and luminance unevenness is small.
　本発明の形態を用いる事により、互いに並設された線光源間の中間地点および／または冷陰極管直上における輝度比を向上し、均一な輝度分布を得ることができる第一の光学シートと、直下型光源装置、液晶表示装置を提供でき産業上極めて有用である。 By using the form of the present invention, the first optical sheet capable of improving the luminance ratio at the intermediate point between the line light sources arranged in parallel with each other and / or directly above the cold cathode tube, and obtaining a uniform luminance distribution; A direct light source device and a liquid crystal display device can be provided, which is extremely useful in industry.
１：冷陰極管ランプ
２：反射フィルム
３：第一の光学シート
４：第二の光学シート
５：第三の光学シート
６：第四の光学シート
７：前面パネル 1: Cold cathode tube lamp 2: Reflecting film 3: First optical sheet 4: Second optical sheet 5: Third optical sheet 6: Fourth optical sheet 7: Front panel

Claims (21)

  1. 　表面に直線畝状に形成された凸状のレンズ群を有する光学シートであって、
    　該レンズ群の長さ方向に対する垂直断面形状における全てのレンズの凸状部外周線が、曲線および／または直線で構成され、かつ、
    　前記曲線上の全ての点における接線および／または前記直線と基底線のなす角度（θ）がθ≧４０°である部分（Ｘ1）と、
    　前記曲線上の全ての点における接線および／または前記直線と基底線のなす角度（θ）が２５°≦θ≦３５°である部分（Ｘ2）を含み、
    　前記部分（Ｘ1）の前記レンズ群の基底線に投影した長さ（ｘ1）の総計（ｘ1total）が、前記レンズ群の基底線の長さの総計（Ｐtotal）の２５％以上６０％以下であり、かつ、前記部分（Ｘ2）の該レンズ群の基底線に投影した長さ（ｘ2）の総計（ｘ2total）が、前記レンズ群の基底線の長さの総計（Ｐtotal）の２５％以上６０％以下であることを特徴とする光学シート。     An optical sheet having a convex lens group formed in a linear bowl shape on the surface,
    The convex portion outer peripheral lines of all the lenses in the vertical cross-sectional shape with respect to the length direction of the lens group are configured by a curve and / or a straight line, and
    A portion (X 1 ) where tangents at all points on the curve and / or an angle (θ) formed by the straight line and the base line is θ ≧ 40 °, and
    A portion (X 2 ) where tangents at all points on the curve and / or an angle (θ) formed by the straight line and the base line is 25 ° ≦ θ ≦ 35 °,
    The total length (x 1total ) of the length (x 1 ) projected on the base line of the lens group of the portion (X 1 ) is 25% or more of the total length (P total ) of the base line length of the lens group 60 % And the total length (x 2total ) of the length (x 2 ) projected onto the base line of the lens group of the portion (X 2 ) is the total length (P 2 ) of the base line length of the lens group (P 2 total ) is 25% or more and 60% or less.
  2. 　前記レンズ群が、
    　単位レンズの長さ方向に対する垂直断面形状における凸状部外周線が曲線を主体に構成され、かつ、前記曲線上の全ての点における接線と基底線のなす角度（θ11）がθ11≧４０°である曲線部（Ｒ11）と、その曲線上の全ての点における接線と基底線のなす角度（θ12）が２５°≦θ12≦３５°である曲線部（Ｒ12）を含み、
    　前記曲線部（Ｒ11）の該単位レンズ形状の基底線に投影した長さの総計（ｒ11）の前記基底線の全長に対する割合が２５％以上６０％以下であり、かつ、前記曲線部（Ｒ12）の該単位レンズ形状の基底線に投影した長さの総計（ｒ12）の前記基底線の全長に対する割合が２５％以上６０％以下である第１単位レンズを有する請求項１に記載の光学シート。     The lens group is
    The outer peripheral line of the convex portion in the vertical cross-sectional shape with respect to the length direction of the unit lens is mainly composed of a curve, and the angle (θ 11 ) between the tangent line and the base line at all points on the curve is θ 11 ≧ 40. ° a is curved portions and (R 11), wherein the angle between the tangent and the base line at all points on the curve (theta 12) is curved section is 25 ° ≦ θ 12 ≦ 35 ° (R 12),
    The ratio of the total length (r 11 ) of the curved portion (R 11 ) projected to the base line of the unit lens shape to the total length of the base line is 25% or more and 60% or less, and the curved portion ( according to claim 1 having the unit first unit lens the ratio of the total length of the base line of the lens projected length total to baseline shape (r 12) is 60% or less than 25% of the R 12) Optical sheet.
  3. 　前記第１単位レンズが、前記曲線部（Ｒ11）と前記曲線部（Ｒ12）を２つずつ含有する請求項２に記載の光学シート。 3. The optical sheet according to claim 2, wherein the first unit lens contains two curved portions (R 11 ) and two curved portions (R 12 ).
  4. 　前記曲線部（Ｒ11）が、二次曲線の一部である請求項２または３に記載の光学シート。 The optical sheet according to claim 2 or 3, wherein the curved portion (R 11 ) is a part of a quadratic curve.
  5. 　前記レンズ群が、
    　単位レンズの長さ方向に対する垂直断面形状における凸状部外周線が２つ以上の曲線と１つ以上の直線が連結した形状から構成され、かつ、前記曲線の少なくとも２つが、その曲線上の全ての点における接線と基底線のなす角度（θ21）がθ21≧４０°である曲線部（Ｒ21）を含み、前記直線（Ｒ22）と基底線のなす角度（θ22）が２５°≦θ22≦３５°である第２単位レンズを有する請求項１に記載の光学シート。     The lens group is
    The outer peripheral line of the convex portion in the vertical cross-sectional shape with respect to the length direction of the unit lens is composed of a shape in which two or more curves and one or more straight lines are connected, and at least two of the curves are all on the curve Including a curved line portion (R 21 ) in which the angle (θ 21 ) between the tangent line and the base line is θ 21 ≧ 40 °, and the angle (θ 22 ) between the straight line (R 22 ) and the base line is 25 °. The optical sheet according to claim 1, comprising a second unit lens satisfying ≦ θ 22 ≦ 35 °.
  6. 　前記第２単位レンズは、単位レンズの長さ方向に対する垂直断面形状における凸状部外周線が、２つ以上の曲線と２つ以上の直線が連結した形状から構成される請求項５に記載の光学シート。 6. The second unit lens according to claim 5, wherein the outer peripheral line of the convex portion in the vertical cross-sectional shape with respect to the length direction of the unit lens is configured by connecting two or more curves and two or more straight lines. Optical sheet.
  7. 　前記曲線のうち、少なくとも２つが、二次曲線の一部である請求項５または６に記載の光学シート。 The optical sheet according to claim 5 or 6, wherein at least two of the curves are part of a quadratic curve.
  8. 　前記第２単位レンズは、前記曲線を該単位レンズ形状の基底線に投影した長さの総計（Ｖ）と、直線を該単位レンズ形状の基底線に投影した長さの総計（Ｗ）の割合（Ｖ：Ｗ）が、１５：８５以上８５：１５以下である請求項５～７のいずれか一項に記載の光学シート。 The second unit lens has a ratio of a total length (V) obtained by projecting the curve onto the base line of the unit lens shape and a total length (W) obtained by projecting a straight line onto the base line of the unit lens shape. The optical sheet according to any one of claims 5 to 7, wherein (V: W) is 15:85 or more and 85:15 or less.
  9. 　前記第１または第２単位レンズの長さ方向に対する垂直断面形状における基底線の長さ（Ｐ）と、基底線からレンズ頂部までの高さ（Ｈ）の割合（Ｈ／Ｐ）が、０．２５以上０．７５以下である請求項２～８に記載の光学シート。 The ratio (H / P) of the length (P) of the base line in the vertical cross-sectional shape with respect to the length direction of the first or second unit lens and the height (H) from the base line to the top of the lens is 0. The optical sheet according to any one of claims 2 to 8, which is 25 or more and 0.75 or less.
  10. 　前記第１または第２単位レンズの基底部分の面積合計が、出光面全体の５０面積％以上である請求項２～９に記載の光学シート。 10. The optical sheet according to claim 2, wherein the total area of the base portion of the first or second unit lens is 50 area% or more of the entire light exit surface.
  11. 　前記レンズ群が、前記第１または第２単位レンズのみで構成されている請求項２～１０に記載の光学シート。 The optical sheet according to any one of claims 2 to 10, wherein the lens group includes only the first or second unit lens.
  12. 　前記レンズ群が、長さ方向に対する垂直断面形状の凸状部外周線として、下記の形状１を有する単位レンズおよび形状２を有する単位レンズを有する請求項１に記載の光学シート。
    　≪形状１≫
    　外周線が曲線または直線からなり、かつ、その曲線上の全ての点における接線または直線と該単位レンズ断面形状の基底線がなす角度（θ32）が２５°≦θ32≦３５°である部分（Ｒ32）を含み、前記部分（Ｒ32）の該単位レンズ断面形状の基底線に投影した長さの総計（ｒ32）が、該単位レンズ断面形状の基底線全長に対して９０％以上であることを特徴とする形状。
    　≪形状２≫
    　外周線が曲線部を主体に構成され、かつ、単一の二次曲線で表される部分（Ｒ33）の該単位レンズ形状の基底線に投影した長さの総計（ｒ33）が、該単位レンズ形状の基底線全長に対して９０％以上であり、かつ前記部分（Ｒ33）の一部として、その曲線上の全ての点における接線と基底線のなす角度（θ31）が、θ31≧４０°である曲線部（Ｒ31）を含み、前記曲線部（Ｒ31）の該レンズ断面形状の基底線に投影した長さの総計（ｒ31）の基底線全長に対する割合が２０％以上であることを特徴とする形状。     2. The optical sheet according to claim 1, wherein the lens group includes a unit lens having the following shape 1 and a unit lens having the shape 2 as a convex portion outer peripheral line having a vertical cross-sectional shape with respect to the length direction.
    ≪Shape 1≫
    A portion in which an outer peripheral line is a curve or a straight line, and an angle (θ 32 ) between a tangent or a straight line at all points on the curve and a base line of the unit lens cross-sectional shape is 25 ° ≦ θ 32 ≦ 35 ° (R 32 ), and the total length (r 32 ) of the portion (R 32 ) projected onto the base line of the unit lens cross-sectional shape is 90% or more with respect to the total base line length of the unit lens cross-sectional shape A shape characterized by
    ≪Shape 2≫
    The total length (r 33 ) projected on the base line of the unit lens shape of the portion (R 33 ) whose outer peripheral line is mainly composed of a curved portion and is represented by a single quadratic curve, The angle (θ 31 ) between the tangent line and the base line at all points on the curve is 90% or more with respect to the total length of the base line of the unit lens shape and is a part of the portion (R 33 ). Including the curved portion (R 31 ) where 31 ≧ 40 °, the ratio of the total length (r 31 ) of the curved portion (R 31 ) projected to the baseline of the lens cross-sectional shape to the total length of the baseline is 20% A shape characterized by the above.
  13. 　前記形状１を有する単位レンズおよび形状２を有する単位レンズの基底線の面積合計が、出光面全体の８０面積％以上である請求項１２に記載の光学シート。 The optical sheet according to claim 12, wherein the total area of the base lines of the unit lens having the shape 1 and the unit lens having the shape 2 is 80 area% or more of the entire light emitting surface.
  14. 　出光面全体に対するそれぞれの投影面積の合計として、形状１を有する単位レンズと形状２を有する単位レンズの面積比（形状１／形状２）が、０．０５以上２．０以下である請求項１２または１３に記載の光学シート。 The area ratio (shape 1 / shape 2) of the unit lens having the shape 1 and the unit lens having the shape 2 is 0.05 or more and 2.0 or less as the sum of the respective projection areas on the entire light exit surface. Or the optical sheet of 13.
  15. 　前記形状１を有する単位レンズの長さ方向に対する垂直断面形状における基底線の長さ（Ｌ１）と基底線からレンズ頂点までの高さ（Ｈ１）の割合（Ｈ１／Ｌ１）が、０．２０以上０．４０以下であり、前記形状２を有する単位レンズの長さ方向に対する垂直断面形状における基底線の長さ（Ｌ２）と基底線からレンズ頂点までの高さ（Ｈ２）の割合（Ｈ２／Ｌ２）が、０．２５以上０．７５以下である請求項１２～１４のいずれか一項に記載の光学シート。 The ratio (H1 / L1) of the length (L1) of the base line and the height (H1) from the base line to the lens apex in the vertical cross-sectional shape with respect to the length direction of the unit lens having the shape 1 is 0.20 or more. The ratio (H2 / L2) of the length (L2) of the base line and the height (H2) from the base line to the lens apex in the vertical cross-sectional shape with respect to the length direction of the unit lens having the shape 2 of 0.40 or less ) Is 0.25 or more and 0.75 or less, The optical sheet according to any one of claims 12 to 14.
  16. 　前記レンズ群は、該レンズ群の長さ方向に対する垂直断面において、単位レンズの凸状部外周線の頂部と隣り合う単位レンズの凸状部外周線の頂部の間隔が、３００μｍ以下である請求項１～１５のいずれか一項に記載の光学シート。 In the lens group, in the vertical cross section with respect to the length direction of the lens group, the distance between the tops of the convex part outer peripheral lines of the unit lens and the convex part outer peripheral lines of the unit lens adjacent to each other is 300 μm or less. The optical sheet according to any one of 1 to 15.
  17. 　光学シートを構成する材料が、透明性熱可塑性樹脂と、該熱可塑性樹脂と屈折率が異なる平均粒子径が０．１μｍ以上５０μｍ以下の微粒子を含有し、
    　前記微粒子の配合量が、前記熱可塑性樹脂１００質量部に対し、０．０１質量部以上１０質量部以下である請求項１～１６のいずれか一項に記載の光学シート。     The material constituting the optical sheet contains a transparent thermoplastic resin and fine particles having a refractive index different from that of the thermoplastic resin and having an average particle diameter of 0.1 μm or more and 50 μm or less,
    The optical sheet according to any one of claims 1 to 16, wherein a blending amount of the fine particles is 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.
  18. 　請求項１～１７の光学シートの表面形状を形成する為の正対する母型を利用することを特徴とする光学シートの製造方法。 18. A method for producing an optical sheet, characterized in that a master matrix facing directly to form the surface shape of the optical sheet according to claim 1 is used.
  19. 　請求項１～１８のいずれか一項に記載の光学シートとプリズムシートを必須とすることを特徴とする表示装置用光源装置。 A light source device for a display device, characterized in that the optical sheet and the prism sheet according to any one of claims 1 to 18 are essential.
  20. 　複数の線光源と、該線光源間に配された複数の支持ピンと、該支持ピン上に載置された３枚の光学シート群とを有する直下型光源装置であって、
    　前記光学シート群が、請求項１７に記載の光学シート、プリズムシートおよび光拡散シートのみから構成されていることを特徴とする表示装置用直下型光源装置。     A direct type light source device having a plurality of line light sources, a plurality of support pins arranged between the line light sources, and three optical sheet groups placed on the support pins,
    A direct light source device for a display device, wherein the optical sheet group includes only the optical sheet, the prism sheet, and the light diffusion sheet according to claim 17.
  21. 　請求項１９または２０に記載の表示装置用光源装置を含むことを特徴とする表示装置。 A display device comprising the light source device for a display device according to claim 19 or 20.
PCT/JP2009/068522 2008-10-28 2009-10-28 Optical sheet, optical sheet manufacturing method, light source including optical sheet, and display device WO2010050522A1 (en)

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