JP4622664B2 - Planar light emitter - Google Patents

Description

  The present invention relates to a planar light emitter suitable for a direct backlight as a planar light source, and particularly suitable for a direct backlight for a planar light source used in a flat display device such as a liquid crystal display device. It is about.

  In recent years, many displays using liquid crystals have been used as display devices for personal computers, televisions, mobile phones, and the like. Since these liquid crystal displays themselves are not light emitters, they can be displayed by irradiating light from the back side using a surface light source. In addition, in order to meet the requirement that the surface light source not only irradiate light but also irradiate the entire screen uniformly, a surface light emitter called a sidelight type backlight or a direct type backlight is adopted. Yes.

  Among these, a direct type backlight applied to a television or the like will be described with reference to the conceptual diagram of FIG. In direct-type backlights, generally, a plurality of fluorescent tubes 3 arranged in parallel and a milky white diffusion plate 1 are installed on the upper surface side of the fluorescent tube 3, and in some cases, on the diffusion plate 1 Other diffusion sheets, prism sheets, and the like may be appropriately disposed. A light reflecting film 2 is laid on the lower surface side of the fluorescent tube 3.

  First, the fluorescent tube 3 serves as a light source. By using these light sources, a backlight for applications such as liquid crystal can be illuminated. In many cases, a linear cold cathode tube (fluorescent tube) is used for the fluorescent tube 3, but an organic EL, an LED, or the like may be used as another example of the light source.

  Next, the diffuser is typically a white diffuser in which diffusible particles are dispersed in acrylic resin or the like. In the direct type backlight, the image of the lamp installed on the back is reduced, and the uniformity is reduced. It has the effect | action which improves.

  On the other hand, there is an increasing demand for brighter surface light sources (higher brightness), and there are methods such as increasing the number of light sources and increasing output, but these methods are significant. It causes cost increase and is inefficient.

  In addition, with respect to the above demand for higher brightness, proposals have been made regarding anisotropic diffusion films for diffusion plates. Specifically, a cylindrical lens portion provided in a stripe shape (see Patent Document 1), a rod-shaped bubble dispersed (see Patent Document 2), and a vertically split spindle shape (see Patent Document 3) ) Etc. have been proposed.

  Next, as a light reflection film, a high reflection function is required at the same time as a thin film. Conventionally, a film added with a white pigment or a film containing fine bubbles inside is used alone or these films. A laminate of a metal plate, a plastic plate and the like has been used. In particular, when a film containing fine bubbles inside is used, it is widely used because of its excellent brightness improvement effect and uniformity. Such fine bubbles can be obtained by causing a resin to contain an incompatible component (void nucleating agent) and stretching it in one or more directions. Such a film containing fine bubbles inside is disclosed in a patent publication (Patent Document 4).

Of course, to improve the uniformity of the surface light source and to increase the brightness, an approach by improving the light reflection film has been made. Specifically, by increasing the amount of white pigment added, the light reflection property of the light reflection film is improved, and the light reflection film is designed to increase the brightness, or the light reflection film is deformed according to the arrangement of the light source, Some have been proposed that aim to improve the uniformity by controlling the light emission direction (for example, Patent Documents 5 and 6).
JP 2002-62528 A (Claim 1, Claim 4-5, FIG. 1) JP 2002-98810 A (Claim 1, FIG. 1) JP 2002-107510 A (Claim 2-3, FIG. 1) JP-A-6-322153 (column 0010, Example 1) JP-A-2001-318614 (Claim 1, columns 0012, 0013, 0037, FIG. 1) JP-A-2002-82624 (Claim 1, No. 0009, No. 0023, No. 0025, FIGS. 1 and 2)

  However, the conventional techniques have the following problems.

  First, with regard to the light diffusing plate, neither the conventional milky white plate nor the above-mentioned proposals have particularly high brightness and uniformity in the direct type backlight, and a high balance between productivity and cost. There is a problem of not being able to let it.

  Next, with respect to the light reflecting film, there is a problem that even if the light reflectivity is simply improved, the surface light source luminance is not improved as much as expected. Another problem is that even if the light reflecting film is simply deformed, the effect of improving luminance unevenness is low in cost.

  Therefore, in view of these points, an object of the present invention is to provide a novel planar light emitting body having high brightness and high uniformity by paying attention to the interaction between the light reflection film and the light diffusion film.

In order to solve the above problems, the present invention has the following configuration.
1. At least, the planar light emitter having a light reflecting plate satisfying the following requirements A, a light source having a plurality of straight lines, and the anisotropic diffusion film that satisfies the requirements of B.
A It is a light reflection film whose cross-sectional shape of the direction orthogonal to the length direction of a linear light source is a continuous shape comprised from a mountain-shaped part and a bottom face part.
B An anisotropic diffusion film in which a plurality of lens columns having the following cross-sectional shape are installed on at least one surface of a base material in parallel with the surface direction of the film.
Sectional shape: the surface portion of the lens pillars, made from the curve, and the height LB of the cross section, the lens pillars rather long than half the length LA of the bottom in contact with the substrate, and the vertex of the lens pillars between The distance CL is 200 μm or less.
2. The planar light-emitting body, wherein the cross-sectional shape of the anisotropic diffusion film is a part of a substantially elliptical shape and has a relationship of the formula (1).
x2 / a2 + (y + k) 2 / b2 = 1 (1)
However, y ≧ 0, b / a> 1, b> k ≧ 0.
Here, (x, y) represents the surface coordinates in the cross section of the lens column, and the thickness direction of the film is the y-axis direction and the film surface direction is the x-axis direction. Further, the center of the portion where the lens column contacts the base material is x = 0, and the contact surface with the base material is y = 0.
3. Any of the planar light emitters described above, wherein an anisotropic diffusion film having LB / LA of 0.75 or more is used.
4). Any one of the planar light emitters described above, wherein a light reflecting film having an angle of apex of the chevron is 70 ° to 110 ° is used.
5. Any one of the planar light emitters described above, wherein a light reflecting film in which the apex height H of the chevron portion satisfies the following relationship is used.
H ≧ L / 2
Where L is the distance between the center of the linear light source and the bottom of the light reflector film
6 . Any one of the planar light emitters which is a direct type backlight of a display device.

  Since the planar light emitter of the present invention is composed of at least a plurality of linear light sources, a light reflecting plate that satisfies the requirement of A, and an anisotropic diffusion film that satisfies the requirement of B, the front luminance is improved. And brightness unevenness improvement (screen uniformity), it can illuminate the liquid crystal screen and make the liquid crystal image clearer and easier to see.

The planar light emitter of the present invention needs to be composed of at least a light reflecting film that satisfies the requirement of A, a light source having a plurality of linear shapes, and an anisotropic diffusion film that satisfies the requirement of B.
A light reflecting film in which the cross-sectional shape in the direction perpendicular to the straight line in the form of the light source is a continuous shape composed of a mountain-shaped portion and a bottom surface portion.
B An anisotropic diffusion film in which a plurality of lens columns having the following cross-sectional shape are installed on at least one surface of a substrate in parallel to the surface direction of the film.
Cross-sectional shape: The surface portion of the lens column is a curve, and the height LB of the cross-section is longer than ½ of the length LA of the bottom where the lens column contacts the substrate.

Furthermore, it is preferable that the cross-sectional shape of an anisotropic diffusion film is a part of substantially ellipse, and is a planar light-emitting body characterized by having the relationship of Formula (1).
^{x 2 / a 2 + (y} + k) 2 / b 2 = 1 (1)
However, y ≧ 0, b / a> 1, b> k ≧ 0.

  Here, (x, y) represents the surface coordinates in the cross section of the lens column, and the thickness direction of the film is the y-axis direction and the film surface direction is the x-axis direction. Further, the center of the portion where the lens column contacts the base material is x = 0, and the contact surface with the base material is y = 0.

  As a light source having a plurality of linear shapes, in addition to the case where a plurality of linear light sources 4 as shown in FIG. 2 are arranged, U-shaped including two or more linear shapes as shown in FIGS. It may be constituted by a light source 4 such as a shape. The plurality of straight lines of the light source shape are preferably parallel.

  When two or more straight portions are formed in a U-shape or the like, even if there are two or more straight portions, a single light source is included in a light source having a plurality of straight shapes. The term “multiple” means two or more.

  Next, the planar light-emitting body of the present invention is a light reflecting film in which the cross-sectional shape in the vertical direction is a repetition of a basic unit consisting of a mountain-shaped portion and a bottom surface portion with respect to the length direction of the straight line shape of the light source. It is necessary to have a light reflector. The length direction of the light source refers to the length direction of the linear portion of the light source described above. The cross-sectional shape of the light reflecting film perpendicular to the direction is the above shape.

  A chevron part is comprised from a curve or a straight line, and points out the shape convex to the light source side. FIG. 5 is a perspective view showing a state in which the light reflecting film 2 is arranged under the light source 4 and FIG. In addition, FIG. 8 and 9 may be used. Among them, a shape constituted by two straight lines as shown in FIG. 6, a shape constituted by one curve as shown in FIG. 7, a shape constituted by two curves as shown in FIG. 8, and FIG. As shown in FIG. 4, it is preferable from the viewpoint of productivity that the shape is composed of two straight lines and one curved line.

  The point having the maximum height is the vertex 5. In the case of a shape constituted by straight lines as shown in FIG. 6, the apex angle is preferably 70 ° or more and 110 ° or less. More preferably, it is 80 ° or more and 100 ° or less. The distribution of light emitted from the light source can be controlled efficiently by setting the apex angle to such a range, or when the anisotropic diffusion film described later is combined, the uniformity and the surface light source luminance are dramatically improved. Can do.

  In addition, when making a light-reflective film by bending and forming a mountain-shaped part, a vertex part (bending part) may not be a corner | angular but may be rounded slightly. In the case of bending, it is difficult to avoid such a phenomenon, so that the apex angle 8 can be obtained by extending two straight lines / curves constituting the chevron as shown in FIG.

  As shown in FIG. 11, the cross-sectional length TL of the bottom surface portion 7 in the light reflecting film is not less than the cross-sectional length KN of the light source 4 (corresponding to the thickness if the fluorescent tube is used), and is not more than half of the inter-light source distance KL. Preferably there is. If the cross section length TL of the bottom surface portion is in such a range, the emitted light from the light source can be controlled efficiently, or when the anisotropic diffusion film described later is combined, the uniformity and the surface light source luminance will jump. Can be improved.

  It is preferable that the cross-sectional shape of the light reflecting film constituting the backlight of the present invention is a repetition of a basic shape composed of one type of chevron and one type of bottom. This is because when there are different types of chevron portions and bottom surface portions, the control of the light emitted from the light source is not uniform, and the screen uniformity may deteriorate.

  Accordingly, in the present invention, it is preferable that the light reflecting film has a ridge line of the mountain-shaped portion or a valley line formed by the mountain-shaped portion and the bottom surface portion in parallel with the linear portion of the light source. However, the portion corresponding to the screen edge of the display device is not necessarily required. This is because the end of the screen is close to the side surface of the screen, and it may be physically impossible to have the basic shape described above.

Furthermore, in the present invention, it is preferable that the peak height H of the chevron satisfies the following relationship.
H ≧ L / 2
Here, as shown in FIG. 12, L is the distance between the center of the light source and the bottom of the reflector. More preferably, H ≧ L × 3/4
It is. There is no particular upper limit. FIG. 13 shows a cross section of a surface light emitter configured in the order of the light reflection film 2, the light source 4, and the anisotropic diffusion film 9, because the anisotropic diffusion film 9 is provided on the light source 4. The upper limit is a height that does not contact the anisotropic diffusion film 9.

  If the peak position of the chevron is within this range, the emitted light from the light source can be controlled efficiently, or when the anisotropic diffusion film described later is combined, the uniformity and the surface light source brightness are further improved. Can be made.

  The light reflectance of the light reflecting film used in the present invention is preferably 85% or more, more preferably 87% or more, and particularly preferably 90% or more. If the light reflectance is low, the light emitted from the light source cannot be sufficiently reflected, and the screen brightness may be extremely inferior.

Moreover, the following are illustrated as a material of a light reflection film.
1) A resin used as a main constituent, to which organic or inorganic dyes and fine particles are added.
2) One or more materials selected from a resin incompatible with the resin component and organic particles and inorganic particles are mixed in the resin, melt extruded, and then stretched in at least one direction to form fine bubbles inside. Things.
3) A gas such as carbon dioxide is injected into a molten resin, extruded and molded, and has bubbles inside.
There is no particular limitation as long as it has apparent whiteness. In particular, in the application of the present invention, the above two are preferable.

  Further, a thermoplastic resin to which organic or inorganic fine particles are added is laminated on at least one side of a film in which fine bubbles are formed inside by a method such as co-extrusion, and further stretched, and finer bubbles are formed on the surface layer portion than the inner layer portion. A composite film formed with is particularly preferred.

  Although it will not specifically limit as resin which comprises a light reflection film if it can form a film, As a preferable thing, resin which can be melt-extruded is preferable. Specific examples include polyester, polyolefin, polyamide, polyurethane, polyphenylene sulfide and the like. In particular, in the present invention, polyester is preferable from the viewpoints of good dimensional stability and mechanical properties and little absorption in the visible light region.

  Specific examples of the polyester include polyethylene terephthalate (hereinafter abbreviated as PET), polyethylene-2,6-naphthalene dicarboxylate (hereinafter abbreviated as PEN), polypropylene terephthalate, polybutylene terephthalate, and poly-1,4-. Examples include cyclohexylene dimethylene terephthalate. Of course, these polyesters may be homopolymers or copolymers. A homopolymer is preferable. Examples of the copolymer component in the case of a copolymer include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and diol components having 2 to 15 carbon atoms. Examples of dicarboxylic acids include, for example, isophthalic acid. Acid, adipic acid, sebacic acid, phthalic acid, sulfonate group-containing isophthalic acid, and ester forming compounds thereof, and diol components include diethylene glycol, triethylene glycol, neopentyl glycol, polyalkylene glycol having a molecular weight of 400 to 20,000 And so on.

  In these polyesters, various additives such as heat stabilizers, oxidation stabilizers, organic lubricants, organic and inorganic fine particles, light stabilizers, antistatic agents, nucleating agents, as long as the effects of the present invention are not impaired. A coupling agent or the like may be added.

  The light reflecting film used in the present invention preferably contains a material imparting light resistance, that is, a light stabilizer, in order to stably exhibit reflection characteristics over a long period of time. Furthermore, the outermost surface layer preferably contains a light stabilizer. Here, the outermost surface layer refers to a layer located on the most film surface side when the light reflecting film has a laminated structure in the film thickness direction. On the other hand, when the film has a single-layer structure, it refers to the layer. In addition, since the film has two front and back surfaces, there can be two outermost layers in the case of a laminated film. It is preferable to produce the outermost surface layer containing the agent. As light stabilizers, materials that have the function of shielding and absorbing ultraviolet rays, materials that decompose non-radical hydroperoxides generated by ultraviolet irradiation, materials that quench the excited state by light, and radicals generated by ultraviolet irradiation are captured. The material to be illustrated is illustrated. For example, hindered amine-based, salicylic acid-based, benzophenone-based, benzotriazole-based, cyanoacrylate-based, triazine-based, benzoate-based, oxalic acid anilide-based organic light stabilizers, copolymer polymers containing these light-stabilized structures, or sol-gels Inorganic light stabilizers such as can be used. Specific examples of the light stabilizer suitably used are shown below, but of course not limited thereto. Moreover, it is also a preferable aspect to use these in combination.

  Hindered amines: bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine Polycondensate.

  Salicylic acid type: pt-butylphenyl salicylate, p-octylphenyl salicylate.

  Benzophenone series: 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2,2′-4,4′-tetrahydroxybenzophenone, 2,2 ′ -Dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, bis (2-methoxy-4-hydroxy-5-benzoylphenyl) methane.

  Benzotriazole series: 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-t-butylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′) , 5'-di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy- 3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-5'-t-octylphenol) benzotriazole, 2- (2'-hydroxy-3', 5 '-Di-t-amylphenyl) benzotriazole, 2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-ben Triazol-2-yl) phenol], 2 (2′hydroxy-5′-methacryloxyphenyl) -2H-benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 "-tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2- (2'-hydroxy-5-acryloyloxyethylphenyl) -2H-benzotriazole, 2- (2'-hydroxy-5'-methacrylic) Roxyethylphenyl) -2H-benzotriazole, 2- (2′-hydroxy-3′-t-butyl-5′-acryloylethylphenyl) -5-chloro-2H-benzotriazole.

  Cyanoacrylate series: Ethyl-2-cyano-3,3'-diphenylacrylate.

  Other than the above: nickel bis (octylphenyl) sulfide, [2,2′-thiobis (4-tert-octylphenolate)]-n-butylamine nickel, nickel complex-3,5-di-t-butyl-4-hydroxy Benzyl phosphate monoethylate, nickel dibutyldithiocarbamate, 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate, 2,4-di-t-butyl Phenyl-3 ′, 5′-di-t-butyl-4′-hydroxybenzoate, 2-ethoxy-2′-ethyl oxac acid bisanilide, 2- (4,6-diphenyl-1,3,5-triazine -2-yl) -5-[(hexyl) oxy] -phenol.

In the planar light-emitting body of the present invention, the materials constituting the light reflecting film can be used in combination according to the application. For example, it is a preferable embodiment to bond with a colored film such as black or a metal foil when light is not expected to leak to the back of the light reflecting film. Specific examples of suitably used composite means are shown below, but of course not limited thereto.
Composite partner materials: polyester film, polyolefin film, polyamide film, polyurethane film, polyphenylene sulfide film, aluminum foil, iron foil, copper foil.
Composite method: Adhesion, adhesion, heat fusion.
Moreover, it is also one of the preferable aspects that a light shielding layer, a heat-transfer layer, and a conductive layer are formed on the back side of the material constituting the reflector by printing or vapor deposition.

  Moreover, the means in particular of the said shape light reflection film is not restrict | limited. For example, it is also one of preferable processing modes that one light reflecting film is formed into the above shape by bending or the like, or the light reflecting film is bonded to an aluminum plate or the like and formed into the above shape by pressing.

In the planar light-emitting body of the present invention, in addition to the above-described light reflecting film and light source, a plurality of lens columns having the following cross-sectional shape are disposed in parallel and in the surface direction of the film on at least one surface of the substrate. It is necessary that an anisotropic diffusion film is provided.
Cross-sectional shape: The surface portion of the lens column is a curve, and the height LB of the cross-section is longer than ½ of the length LA of the bottom where the lens column contacts the substrate.
Furthermore, it is preferable that the cross-sectional shape of the anisotropic diffusion film is a part of a substantially elliptical shape and has a relationship of the formula (1).
^{x 2 / a 2 + (y} + k) 2 / b 2 = 1 (1)
However, y ≧ 0, b / a> 1, b> k ≧ 0.
(Here, (x, y) represents the surface coordinates in the cross section of the lens column, the film thickness direction is the y-axis direction, and the film surface direction is the x-axis direction. Further, the lens column is in contact with the substrate. The center of the substrate is x = 0, and the contact surface with the substrate is y = 0.)
In the case of a semi-elliptical shape, the distances a and b are as shown in FIG. The cross-sectional shape of the lens column of the anisotropic diffusion film used in the present invention is more preferably a semi-elliptical shape as much as possible, but may be a substantially elliptic shape. Here, with respect to the range of the substantially ellipse, the deviation rate S is preferably 10% or less, more preferably 5% or less, and even more preferably 3% or less with respect to the ideal ellipse. If the deviation rate S exceeds 10%, a desired light diffusion effect may not be obtained. Here, the deviation rate S is obtained as follows.

  First, the cross-sectional shape of the lens column is traced on the xy coordinates. At this time, the center of the portion where the lens column contacts the base material is x = 0, and the contact surface with the base material is y = 0.

Next, a curve represented by equation (1) is drawn on the same coordinates. Next, the lens column cross-sectional length in the x-axis direction of the traced lens column is divided into 100 equal parts. Each x coordinate divided into 100 equal parts is assumed to be x _i (i = 0 to 100). The y value on the curve obtained by tracing the lens column at x _i is y _i , and the y value of the curve shown by the equation (1) is y ′ _i . The divergence rate S is obtained from equation (2).

These three variables are arbitrarily adjusted, and the deviation rate S in the minimum case is adopted.

Incidentally, the minimum deviation rate as efficiency following example as a method of obtaining good, 'sum SS and of the absolute differences for _i, y _i and y' y _i and y with reference to the sum KS of absolute differences of slope in the _i A method for obtaining the deviation rate S is mentioned. SS and KS can be obtained from equations (3) and (4), respectively.

Here, in formula (4), yd _i and yd ′ _i indicate inclinations at (x _i , y _i ) and (x _i , y ′ _i ), respectively. In addition, in equation (4), the sum of i = 1 to 99 is obtained for a complete semi-ellipse, where the slope of the point corresponding to i = 0 and i = 100 is infinite or infinitely small. This is because the points i = 0 and i = 100 are excluded.

Hereinafter, a specific example of a procedure for obtaining the minimum deviation rate will be described.
(A) The variables are b / a, b, and k. In the above description, the variables are a, b, and k. However, even if b / a is used instead of a, a can be obtained from b and b / a. Therefore, b / a is used as a variable here. Next, as an initial value, b / a is set to 3, and k is set to 0.
(Ii) When y = 0, the value of b is adjusted so that the traced curve and the curve of formula (1) are in contact (or have a contact).
(Iii) Adjust the value of k so that SS becomes the minimum value. Note that k must be 0 or more and less than b.
(E) The value of b / a is adjusted so that KS becomes the minimum value. Note that b / a must be greater than 1.
(O) The value of b is adjusted so that SS becomes the minimum value. At this time, b / a must be larger than 1.
(Ka) (U) to (O) are repeated to find the minimum value of S. Here, when (u) to (o) are repeated three times and the numerical value of 3 significant digits (rounded off at the fourth digit) does not change, it is assumed that the minimum deviation rate S is obtained.

  By laying such an anisotropic diffusion film, screen brightness and uniformity can be improved. Although the detailed reason for such an effect is not yet elucidated, the inventors consider as follows. For the direct type backlight, a linear light source such as a linear fluorescent tube is generally used. Therefore, if an anisotropic diffusion film is not used, the image of the linear light source will be visually recognized by the observer. In order to avoid this, light from the light source is scattered in all directions by a light diffusing plate on a milky white plate or the like so as to equalize the screen luminance.

  However, considering that the light source is linear, if the diffusion direction is controlled and a large amount of diffused light can be emitted in the direction perpendicular to the length direction of the light source, the screen luminance can be more efficiently leveled. Conceivable.

  The anisotropic diffusion film used in the present invention lays a curved column (hereinafter referred to as a lens column) formed on the film surface so as to be parallel to the linear light source. A large amount of light can be diffused in the vertical direction. Therefore, it is considered that the light source light can be diffused very efficiently, and a surface light source with high brightness and high uniformity can be obtained.

  Here, the variable a is preferably 400 μm or less. More preferably, it is 200 micrometers or less, More preferably, it is 100 micrometers or less. Since the light emitter of the present invention is a surface light source, it is observed by human eyes. Therefore, the lens column of the anisotropic diffusion film is preferably not visually recognized by human eyes, and is preferably as small as possible. Although a minimum is not specifically limited, It is preferable that it is 1 micrometer or more. If the diameter is smaller than 1 μm, the light incident on the lens does not follow geometric optics, and the components scattered by the wave optics increase, and a desired light diffusivity may not be obtained.

  In addition, the anisotropic diffusion film of this invention may be a transparent body and may be milky white, and is not restrict | limited by film turbidity.

  Further, conventionally, the surface portion of the lens column is a curve, and the height LB of the cross section is shorter than 1/2 of the bottom length LA where the lens column contacts the substrate (for example, the lens column Development of a semicircular cross-sectional shape or a member having a semi-elliptical shape with b / a less than 1 in Formula (1) has been performed. An anisotropic diffusion film having a curved line and having a cross-sectional height LB longer than half of the bottom length LA where the lens column is in contact with the substrate is more anisotropic diffusion than these conventional products. Therefore, the uniformity can be remarkably increased. Furthermore, by using the anisotropic diffusion film used in the present invention, the front luminance can be increased more than that of the conventional product.

  Although the detailed reason why the anisotropic diffusion film used in the present invention exhibits such a unique effect is unknown, the present inventors consider as follows. The angle between the tangent to the curve and the x-axis is made by making the surface portion of the lens column a curve and making the cross-sectional height LB longer than 1/2 of the bottom length LA where the lens column contacts the substrate. Can be increased (that is, approximately 45 ° or more), that is, a portion having a steep angle can be increased. By providing a steep angle, it is considered that the outgoing angle of incident light can be increased, and a good light diffusion ability can be exhibited.

  From this viewpoint, LB / LA is preferably set to 0.75 or more. More preferably, it is 1.0 or more. By setting LB / LA within such a range, the portion having the steep angle can be made larger. The upper limit is not particularly specified, but is preferably 10 or less. This is because when LA / LB is larger than 10, a portion having a steep angle becomes too large, resulting in inferior light transmittance and inferior luminance characteristics.

  Here, LA is preferably 400 μm or less. More preferably, it is 200 micrometers or less, More preferably, it is 100 micrometers or less. Since the light emitter of the present invention is a surface light source, it is observed by human eyes. Therefore, the lens column of the anisotropic diffusion film is preferably not visually recognized by human eyes, and is preferably as small as possible. Although a minimum is not specifically limited, It is preferable that it is 1 micrometer or more. If the diameter is smaller than 1 μm, the light incident on the lens does not follow geometric optics, and the components scattered by the wave optics increase, and a desired light diffusivity may not be obtained.

  Further, by making the cross-sectional shape a substantially semi-elliptical curve with b / a larger than 1, the ratio of the portion where the angle formed by the tangent to the curve and the x axis is large on the curve is efficient. You can do a lot better.

  In this regard, in a member in which the cross-sectional shape of the conventional lens column is a semicircle or a semi-ellipse where b / a is less than 1 in Equation (1), the angle between the tangent to the curve and the x axis is large Even if there is, there is a small proportion of the portion on the curve, so it is considered that a sufficient effect was not obtained.

  As for the cross-sectional shape of the lens column of the anisotropic diffusion film used in the present invention, b / a in formula (1) is preferably 1.2 or more, more preferably 1.5 or more, more preferably 2.0 or more. It is. As described above, since it is considered that anisotropic diffusivity is mainly expressed in a steep portion of the cross-sectional shape of the lens column, it is preferable that b / a (so-called aspect ratio) is large. is there. The upper limit of b / a is not particularly defined, but is preferably 10.0 or less for ease of production.

  In the film cross section of the lens column of the anisotropic diffusion film used in the present invention, the distance CL between the apexes 12 of the lens column is preferably 400 μm or less as shown in FIG. More preferably, it is 200 micrometers or less, More preferably, it is 100 m or less. Since the light emitter of the present invention is a surface light source, it is observed by human eyes. Therefore, the lens column of the anisotropic diffusion film is preferably not visually recognized by human eyes, and is preferably as small as possible. Although a minimum is not specifically limited, It is preferable that it is 1 micrometer or more. If the diameter is smaller than 1 μm, the light incident on the lens does not follow geometric optics, and the components scattered by the wave optics increase, and a desired light diffusivity may not be obtained.

  Here, as shown in FIG. 16, even when there is a gap 13 between one lens column and a lens column adjacent thereto, the distance CL between the vertices 12 is one vertex of one semi-ellipse and a semi-ellipse adjacent thereto. The distance between vertices. Note that such a gap is preferably as small as possible, and more preferably not. Specifically, the gap is preferably 10 μm or less. If there is such a gap, light is emitted from the gap portion without changing the incident angle, so that the uniformity is lowered.

  Moreover, it is preferable that the total light transmittance of the anisotropic diffusion film of this invention is 50% or more. More preferably, it is 65% or more, More preferably, it is 80% or more. Here, the total light transmittance is a value when the light is incident from a surface to which no convex cross section is provided. If the total light transmittance is less than 50%, the luminance characteristics may be inferior.

  From the above viewpoints, polyester resin, acrylic resin, polycarbonate resin, and the like that are excellent in transparency and workability are preferably used as the components of the anisotropic diffusion film used in the present invention, and polyester resin is particularly preferable. Used for.

  Here, polyester is a general term for polymer compounds in which the main bond in the main chain is an ester bond, and can usually be obtained by polycondensation reaction of a dicarboxylic acid component and a glycol component. Here, examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, naphthalenedicarboxylic acid, isophthalic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sodiumsulfonedicarboxylic acid, and phthalic acid. , Oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids, and paraoxybenzoic acid and other oxycarboxylic acids be able to. Examples of the glycol component include aliphatic glycols such as ethylene glycol, propanediol, butanediol, pentanediol, hexanediol and neopentylglycol, polyoxyalkylene glycols such as diethylene glycol, polyethylene glycol and polypropylene glycol, and cyclohexanedimethanol. And alicyclic glycols such as spiroglycol and aromatic glycols such as bisphenol A and bisphenol S.

  Further, the polyester used in the present invention may be a polyester copolymer using two or more of the above dicarboxylic acid components and / or glycol components.

  When the anisotropic diffusion film of this invention is substantially comprised from polyester, it is preferable that the ratio of the polyester to a film is 90 weight% or more, More preferably, it is 95 weight% or more. When the ratio of the polyester is 90% by weight or more, a film excellent in heat resistance and long-term stability can be obtained while having high transparency. Hereinafter, such a film substantially composed of polyester may be simply referred to as a polyester film.

  In the present invention, the thickness FL of the anisotropic diffusion film is preferably 75 to 1000 μm, more preferably 100 to 700 μm, and particularly preferably 150 to 500 μm in terms of film waist and processability. is there. Here, when the lens column is provided only on one surface, the film thickness FL is from the top of the lens column to the surface of the surface where the lens column is not provided as shown in FIG. Thickness. When lens columns are provided on both surfaces, the thickness from the apex of the lens column on one surface to the apex of the lens column on the other surface is shown as shown in FIG.

  In the anisotropic diffusion film of the present invention, various additives such as an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, an organic Lubricants, pigments, dyes, fillers, antistatic agents and nucleating agents may be blended.

  In the present invention, a method of forming a large number of lens columns in parallel on the film surface is a method in which the film is heated as necessary, pressure-bonded between a mold and a flat plate, and the mold surface is transferred, or a mold roll A method of imparting a shape by heating and pressurizing between a roll and a roll is preferred.

  Another preferred method is to apply a photocurable resin on the base film, transfer the shape with a mold, and cure the shape with light.

  The planar light-emitting body of the present invention needs to have the above-described light reflecting film and anisotropic diffusion film. By combining these films, it is possible to obtain a high degree of uniformity and brightness far exceeding the case where each film is used alone. Although the detailed reason for obtaining such an effect is unknown, the present inventors consider as follows.

  The anisotropic diffusion film of the present invention exhibits a certain anisotropic diffusibility for incident light having any incident angle, but is extremely excellent for incident light having an incident angle of 60 ° or less, particularly 45 ° or less. It exhibits anisotropic diffusion.

  Usually, since the light from the linear light source is emitted in all directions, the incident angle of the light incident on the anisotropic diffusion film varies from 0 ° to 90 °.

  However, by making the light reflecting film laid under the light source as described above, the direction of light incident on the anisotropic diffusion film can be controlled. In particular, by adopting the shape of the light reflecting film used in the present invention, most of the light incident on the anisotropic diffusion film can be light having an incident angle of 45 ° or less.

  Therefore, it is considered that by using the light reflecting film and the anisotropic diffusion film of the present invention, high uniformity and luminance characteristics that could not be imagined from the time of using these alone are obtained.

  In addition, as the on-surface light emitter of the present invention, various optical films such as other diffusion films, brightness enhancement films, prism sheets, polarization separation sheets, and color correction films may be used as long as the effects of the present invention are not impaired. it can.

  Next, although the manufacturing method of the planar light-emitting body of this invention is described, this invention is not limited to this.

  First, the manufacturing method of a light reflection film is described.

  In a composite film forming apparatus having a main extruder and a sub-extruder, a mixture of a resin chip that has been sufficiently vacuum-dried and a void nucleating agent as necessary is supplied to a heated main extruder. The addition of the void nucleating agent may be performed using a master chip prepared by uniformly melting and kneading in advance, or may be directly supplied to a kneading extruder. Also, to laminate a thermoplastic resin layer that gives film strength, supply thermoplastic resin chips, inorganic particles, and fluorescent whitening agent that have been sufficiently vacuum-dried as necessary to a heated sub-extruder. To do.

  In this way, the raw materials are supplied to the respective extruders, and laminated (A / B or A / B) so that the polymer (A) of the auxiliary extruder comes to one side of the polymer (B) of the main extruder in the T die composite die. B / A) and co-extrusion into a sheet to obtain a melt-laminated sheet.

  The melt-laminated sheet is tightly cooled and fixed on a cooled drum to produce an unstretched laminated film. At this time, in order to obtain a uniform film, it is desirable to apply static electricity to make it adhere to the drum. Then, the target light reflecting film is obtained through a stretching process, a heat treatment process, and the like as necessary.

  The stretching method is not particularly limited, and there are a sequential biaxial stretching method in which stretching in the longitudinal direction and stretching in the width direction are separated and a simultaneous biaxial stretching method in which stretching in the longitudinal direction and stretching in the width direction are performed simultaneously. As a method of sequential biaxial stretching, for example, the unstretched laminated film is guided to a heated roll group, stretched in the longitudinal direction (longitudinal direction, that is, the traveling direction of the film), and then cooled by a cooling roll group.

  Subsequently, both ends of the film stretched in the longitudinal direction are guided to a heated tenter while being held by clips, and can be stretched in a direction perpendicular to the longitudinal direction (lateral direction or width direction).

  As a method of simultaneous biaxial stretching, for example, by guiding the both ends of the unstretched laminated film with a clip to a heated tenter, stretching in the width direction and simultaneously accelerating the clip traveling speed There is a method of performing stretching in the longitudinal direction simultaneously. This simultaneous biaxial stretching method has an advantage that the film surface does not come into contact with the heated roll, and therefore there is no scratch that becomes an optical defect on the film surface.

  In order to impart planar stability and dimensional stability to the biaxially stretched laminated film thus obtained, heat treatment (heat setting) is subsequently performed in the tenter, and after uniform cooling, cooling to near room temperature and winding up Thus, a light reflecting film having fine bubbles can be obtained.

  After forming a groove by making a linear trace with a ballpoint pen on the crease part of such a light reflecting film, it is folded so that a chevron part and a bottom part are formed, and the whole reflecting film bottom and a reinforcing material are pasted to reinforce did.

  Next, the manufacturing method of an anisotropic diffusion film is described.

  Resin chips that have been sufficiently vacuum-dried as necessary are supplied to a heated main extruder. Then, it extrudes in a sheet form from a nozzle | cap | die, and cools with the cast drum of a mirror surface by an electrostatic application method, and obtains an unstretched sheet. The sheet is biaxially stretched in the longitudinal direction and the transverse direction and heat-treated to obtain a film. An anisotropic diffusion film can be obtained by cooling after heat transfer molding using a mold so that a large number of lens columns are formed on the obtained film.

  The planar light-emitting body of the present invention can be obtained by laying the light reflection film obtained above under a light source having a linear shape and laying a diffusion film thereon.

[Measurement and evaluation method of characteristics]
The following measurements are performed at room temperature (20 ° C. to 30 ° C.), under high humidity conditions (relative humidity of 80% or more), at atmospheric pressure, and in the atmosphere.

(1) Light reflectivity The light reflectivity of 560 nm is obtained with a spectrophotometer U-3410 (Hitachi Ltd.) and a φ60 integrating sphere 130-0632 (Hitachi Ltd.) and a 10 ° tilt spacer attached. It was. In addition, a light reflectance is calculated | required about both surfaces of a light reflection film, and a higher numerical value is made into the light reflectance of the said light reflection film. Part number 210-0740 (alumina) manufactured by Hitachi Instrument Service Co., Ltd. was used for the standard white plate.

(2) Total light transmittance Total light transmittance was measured using a direct reading haze computer HGM-2DP (for C light source). In addition, a total light transmittance is calculated | required about both surfaces of an anisotropic diffusion film, and let a higher numerical value be the total light transmittance of the said anisotropic diffusion film.

(3) Measurement of inter-vertex distance CL First, using a microtome, the film cross section is cut perpendicularly to the length direction of the lens column without being crushed in the thickness direction. Use a scanning electron microscope S-2100A type (Hitachi, Ltd.) for the cut section so that about 2 to 5 cross-sectional shapes can be included in one screen (approx. 500 to 10,000 times as a guide). Magnify and observe. An inter-vertex distance CL is obtained from the obtained cross-sectional image. The n number is 50 or more.

(4) The cross-sectional shape is traced from the cross-sectional image obtained in the measurement (3) of the cross-sectional shape of the anisotropic diffusion film. A curve represented by the equation (1) is approximated to the cross-sectional shape. When the minimum divergence rate S was 10% or less, the curve indicated by the equation (1) was assumed. Moreover, the values of a, b, and k were also obtained by such approximation.

(5) Backlight brightness and uniformity First, as shown in FIG. 19, the distance between the light sources KL (distance between the centers of the fluorescent tubes) of a straight fluorescent tube with a length of 39 cm is 26 mm with respect to the length direction of the fluorescent tube. Install 12 in parallel. The cross-sectional thickness KN (diameter) of the fluorescent tube is 2 mm. Next, a light reflecting film having a rectangular shape (long side: 40 cm, short side: 30 cm) is placed under the fluorescent tube so that the distance L between the light source center and the bottom of the reflector is 10 mm as shown in FIG. Install. Next, the anisotropic diffusion film 9 having a rectangular shape (long side is 40 cm, short side is 30 cm), the distance between the center of each fluorescent tube 3 and the surface portion of the anisotropic diffusion film 9 which is a light diffusion film is 10 mm. Install to be.

  All the fluorescent tubes were turned on, and luminance was measured according to the following method after 1 hour.

  Luminance measurement was performed using EyeScale-3 of Eye System Co., Ltd. The attached CCD camera was installed at a point 1 m from the center of the backlight so as to be in front of the backlight surface. Here, the center of the backlight refers to the center of gravity of the surface of the anisotropic diffusion film.

  The backlight front luminance was an average luminance in a range of 10 cm × 10 cm at the center of the backlight.

The uniformity was determined in the range of 10 cm × 10 cm at the center of the backlight . The homogeneity is preferably 2.0 or less, more preferably 1.5 or less, and still more preferably 1.2 or less. This is because if the degree of uniformity is large, the screen may be difficult to see due to uneven brightness.

(6) Line visibility The backlight incorporating the light reflection film and the diffusion film was observed from the front from a point 1 m away, and it was determined whether the lens column on the anisotropic diffusion film surface was visually recognized as lines. Judgment is made with ◎, ○, △, ×. It shows that it is visually recognized. Even △ can be used practically.

[Examples , comparative examples and reference examples ]
Light reflecting film: Pellets mixed with 89% by weight of PET as the main resin component constituting the light reflecting film, 10% by weight of polymethylpentene as the void nucleating agent, and 1% by weight of polyethylene glycol as the dispersing agent in the main extruder. Further, a sub-extruder was used separately from the main extruder, and pellets mixed with 86% by weight of polyethylene terephthalate (PET) and 14% by weight of calcium carbonate were supplied to the sub-extruder. Next, melt three-layer lamination co-extrusion is performed so that the component layers supplied to the sub-extruder are provided on both surface layers of the component layer supplied to the main extruder, and cooling is carried out on a mirror-cast cast drum by an electrostatic application method to form a three-layer laminate. Created a sheet. The laminated sheet was stretched 3.2 times in the longitudinal direction at a temperature of 87 ° C., and then stretched 3.4 times in the width direction at 110 ° C. through a preheating zone of 95 ° C. with a tenter. Further, heat treatment was performed at 222 ° C. for 30 seconds to obtain a light reflecting film containing a large amount of fine bubbles made of a laminated film having a film thickness of 188 μm. The reflectance of this light reflecting film was 97%.

  Base material for diffusion film: polyethylene terephthalate (hereinafter referred to as “SPG-PET”) containing 0.05% by weight of spherical silica having an average particle size of 0.3 μm from the sub-extruder and 30 mol of spiroglycol copolymerized with respect to glycol units. ), A glass transition temperature of 105 ° C., an intrinsic viscosity of 0.71 dl / g), and polyethylene terephthalate (hereinafter referred to as “PET”) containing 0.1% by weight of spherical silica having an average particle size of 0.3 μm from the main extruder. ), Glass transition temperature 75 ° C.), melt two-layer coextrusion so that the lamination thickness ratio is SPG-PET / PET = 1/2, and cool it on a mirror-cast cast drum by electrostatic application method. A two-layer laminated sheet was produced. The two-layer laminate sheet thus obtained was simultaneously biaxially stretched three times in the longitudinal direction and the transverse direction at a temperature of 110 ° C., and then heat-treated at a temperature of 230 ° C. for 18 seconds to give a polyester having a total film thickness of 250 μm. A film was obtained.

[ Reference Example 1]
The light reflecting film obtained by the above method is linearly marked with a ballpoint pen having a ball diameter of 0.5 mm to form a narrow groove, and further, the apex angle is 120 ° and the height H is 3.3 mm ( H = L / 3), each surface was bent so as to have a flat reflector shape, and installed so that the apex side was located in the middle between the fluorescent tube and the fluorescent tube. At that time, the light reflecting film was fixed to a biaxially stretched polyester film having a thickness of 188 μm (“Lumirror” S10 manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500 manufactured by Nitto Denko Corporation) so that the shape was fixed. Was pasted.

  On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a cross-sectional shape of b / a = 1.3 in the formula (1) is used with a corresponding mold. Transfer molding was performed by heating at a temperature of 130 ° C and further cooling at 20 ° C. The cross-sectional shape, LA, LB, LB / LA, a, b, b / a, k, S, CL of the lens column of the obtained anisotropic diffusion film are as shown in Table 1, and the total light transmittance is 82. %Met.

The surface of the anisotropic diffusion film on which the lens column is provided is directed to the viewer (the surface on which the lens column is not provided is the light source side) (the installation direction of the diffusion film is the same in the following examples and comparative examples). When the backlight was assembled, the homogeneity was 2.0, the average front luminance was 5600 cd / m ² , and the line visibility was Δ, showing good performance.

[ Reference Example 2]
By forming a narrow groove by making a linear groove with a ballpoint pen having a ball diameter of 0.5 mm on the light reflecting film to form a narrow groove, each apex angle is 60 ° and height H is 3.3 mm (H = L / 3). The surface was bent so as to form a reflecting plate composed of a flat surface, and installed so that the apex side was located in the middle of the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by formula (1) (y ≧ 0) with a cross-sectional shape of b / a = 1.3 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The inter-vertex distance CL is 350 μm, and the total light transmittance is 82%.

When this anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.9, the average front luminance was 6000 cd / m ² , and the streak visibility was Δ, showing good performance.

[ Reference Example 3]
By forming a narrow groove by making a linear groove with a ballpoint pen with a ball diameter of 0.5 mm on the light reflecting film to form a narrow groove, each apex angle is 75 ° and height H is 3.3 mm (H = L / 3). The surface was bent so as to form a reflecting plate composed of a flat surface, and installed so that the apex side was located in the middle of the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by formula (1) (y ≧ 0) with a cross-sectional shape of b / a = 1.3 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 350 μm, and the total light transmittance is 82%.

When this anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.7, the average front luminance was 6600 cd / m ² , and the streak visibility was Δ.

[ Reference Example 4]
Each surface is formed with a vertical angle of 90 ° and a height H of 3.3 mm (H = L / 3) by forming grooves by linearly marking the light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm. Was bent so as to form a reflecting plate composed of a flat surface, and placed so that the apex side was located in the middle between the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by formula (1) (y ≧ 0) with a cross-sectional shape of b / a = 1.3 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 350 μm, and the total light transmittance is 82%.

When this anisotropic diffusion film was mounted on a backlight incorporating a light reflection film, the uniformity was 1.6, the average front luminance was 6900 cd / m ² , and the streak visibility was Δ, showing good performance.

[ Reference Example 5]
A groove is formed by pressing a light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm to form a groove, whereby the apex angle is 60 °, the height H is 5 mm (H = L / 2), and each surface is flat. It was bent so as to have the shape of a reflector composed of (1) and placed so that the apex side was located in the middle of the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by formula (1) (y ≧ 0) with a cross-sectional shape of b / a = 1.3 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 350 μm, and the total light transmittance is 82%.

When this anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.4, the average front luminance was 7000 cd / m ² , and the streak visibility was Δ.

[ Reference Example 6]
By forming a groove on the light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm to form a groove, the apex angle is 60 °, the height H is 10 mm (H = L), and each surface is a flat surface. It was bent so as to have the shape of a reflecting plate, and placed so that the apex side was located in the middle of the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by formula (1) (y ≧ 0) with a cross-sectional shape of b / a = 1.3 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 350 μm, and the total light transmittance is 82%.

When this anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.3, the average front luminance was 7400 cd / m ² , and the streak visibility was Δ, showing good performance.

[ Reference Example 7]
Each surface is formed with a vertical angle of 60 ° and a height H of 15 mm (H = 1.5 × L) by forming grooves by linearly marking the light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm. Was bent so as to form a reflecting plate composed of a flat surface, and placed so that the apex side was located in the middle between the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by formula (1) (y ≧ 0) with a cross-sectional shape of b / a = 1.3 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 350 μm, and the total light transmittance is 82%.

When this anisotropic diffusion film was mounted on a backlight incorporating a light reflection film, the uniformity was 1.2, the average front luminance was 8100 cd / m ² , and the streak visibility was Δ, showing good performance.

[ Reference Example 8]
Each surface has a vertical angle of 60 ° and a height H of 3.3 mm (H = L / 3) by forming grooves by linearly marking the light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm. Was bent so as to form a reflecting plate composed of a flat surface, and placed so that the apex side was located in the middle between the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by the formula (1) (y ≧ 0) having a cross-sectional shape of b / a = 1.5 Using a mold, the distance CL between the apexes transferred and molded at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. is 350 μm, and the total light transmittance is 81%.

When this anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.04, the average front luminance was 9200 cd / m ² , and the streak visibility was Δ.

[ Reference Example 9]
Each surface has a vertical angle of 60 ° and a height H of 3.3 mm (H = L / 3) by forming grooves by linearly marking the light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm. Was bent so as to form a reflecting plate composed of a flat surface, and placed so that the apex side was located in the middle between the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by the formula (1) (y ≧ 0) having a cross-sectional shape of b / a = 2.0 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 350 μm, and the total light transmittance is 80%.

When this anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.03, the average front luminance was 9500 cd / m ² , and the streak visibility was Δ.

[Example 10]
Each surface has a vertical angle of 60 ° and a height H of 3.3 mm (H = L / 3) by forming grooves by linearly marking the light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm. Was bent so as to form a reflecting plate composed of a flat surface, and placed so that the apex side was located in the middle between the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by formula (1) (y ≧ 0) with a cross-sectional shape of b / a = 1.3 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 200 μm, and the total light transmittance is 82%.

When such an anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.1, the average front luminance was 8400 cd / m ² , and the streak visibility was good.

[Example 11]
Each surface has a vertical angle of 60 ° and a height H of 3.3 mm (H = L / 3) by forming grooves by linearly marking the light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm. Was bent so as to form a reflecting plate composed of a flat surface, and placed so that the apex side was located in the middle between the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by formula (1) (y ≧ 0) with a cross-sectional shape of b / a = 1.3 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 100 μm, and the total light transmittance is 82%.

When such an anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.1, the average front luminance was 8500 cd / m ² , and the streak visibility was excellent.

[ Reference Example 12]
A groove is formed by pressing a light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm in a straight line to form a groove, whereby the apex angle is 90 °, the height H is 10 mm (H = L), and each surface is a flat surface. It was bent so as to have the shape of a reflecting plate, and placed so that the apex side was located in the middle of the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by formula (1) (y ≧ 0) with a cross-sectional shape of b / a = 1.3 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 350 μm, and the total light transmittance is 82%.

When such an anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.2, the average front luminance was 8200 cd / m ² , and the streak visibility was Δ, showing good performance.

[Example 13]
Each surface has a vertical angle of 60 ° and a height H of 3.3 mm (H = L / 3) by forming grooves by linearly marking the light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm. Was bent so as to form a reflecting plate composed of a flat surface, and placed so that the apex side was located in the middle between the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by the formula (1) (y ≧ 0) having a cross-sectional shape of b / a = 2.0 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 100 μm, and the total light transmittance is 80%.

When this anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.0, the average front luminance was 9400 cd / m ² , and the streak visibility was excellent.

[Example 14]
A groove is formed by pressing a light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm in a straight line to form a groove, whereby the apex angle is 90 °, the height H is 10 mm (H = L), and each surface is a flat surface. It was bent so as to have the shape of a reflecting plate, and placed so that the apex side was located in the middle of the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by the formula (1) (y ≧ 0) having a cross-sectional shape of b / a = 2.0 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 100 μm, and the total light transmittance is 80%.

When such an anisotropic diffusion film was mounted on a backlight incorporating a light reflecting film, the uniformity was 1.0, the average front luminance was 10100 cd / m ² , and the streak visibility was excellent.

[Comparative Example 1]
Instead of the light reflecting film, flat Kenran black paper (reflectance 3%) was laid, and instead of the diffusion film, a 2 mm thick transparent acrylic plate (total light transmittance 90%) was mounted on the backlight. The streak visibility was 、, but the uniformity was so large that it could not be calculated, and the average front luminance was 1500 cd / m ² .

[Comparative Example 2]
A groove is formed by pressing a light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm in a straight line to form a groove, whereby the apex angle is 90 °, the height H is 10 mm (H = L), and each surface is flat. It was bent so as to have the shape of a reflecting plate, and installed so that the apex side was located at the midpoint between the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

  A semicircular stripe-shaped lens having a semicircular cross-sectional shape on the SPG-PET laminated surface of the diffusion film substrate, using a mold with a corresponding shape, at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. Transfer molded. The vertex distance CL is 100 μm, and the total light transmittance is 80%.

  When this diffusion film was mounted on a backlight incorporating a light reflecting film, the streak visibility was ◎, but the uniformity was 2.5 and the average front luminance was 3300 cd / m2.

[Comparative Example 3]
A groove is formed by pressing a light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm in a straight line to form a groove, whereby the apex angle is 90 °, the height H is 10 mm (H = L), and each surface is flat. It was bent so as to have the shape of a reflecting plate, and placed so that the apex side was located in the middle of the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

  On the SPG-PET laminated surface of the diffusion film substrate, a prismatic stripe-shaped lens whose cross-sectional shape has an apex angle of 90 ° is used using a mold having a corresponding shape, a heating temperature of 130 ° C., and a cooling temperature of 20 ° C. To obtain an anisotropic diffusion film 10 having prism lens columns (FIG. 21). The vertex distance CL is 50 μm, and the total light transmittance is 30%.

When such a diffusion film was mounted on a backlight incorporating a light reflecting film, the streak visibility was ◎, but the uniformity was so large that it could not be calculated, and the average front luminance was 3400 cd / m ² .

[Comparative Example 4]
On the SPG-PET laminated surface of the diffusion film substrate, a semi-elliptical stripe-shaped lens having a shape represented by the formula (1) (y ≧ 0) having a cross-sectional shape of b / a = 2.0 Using a mold, transfer molding was performed at a heating temperature of 130 ° C. and a cooling temperature of 20 ° C. The vertex distance CL is 100 μm, and the total light transmittance is 80%.

Instead of the light-reflecting film, flat Kenran black paper (reflectance 3%) was laid, and when the diffusion film was mounted on a backlight incorporating Kenran black paper, streak visibility was ◎ and uniformity was 1.2. However, the average front luminance was 4000 cd / m ² .

[Comparative Example 5]
A groove is formed by pressing a light reflecting film with a ballpoint pen having a ball diameter of 0.5 mm in a straight line to form a groove, whereby the apex angle is 90 °, the height H is 10 mm (H = L), and each surface is a flat surface. It was bent so as to have the shape of a reflecting plate, and placed so that the apex side was located in the middle of the fluorescent tube and the fluorescent tube. At that time, a double-sided adhesive tape (“Lumirror” S10, manufactured by Toray Industries, Inc.) and a double-sided adhesive tape (# 500, manufactured by Nitto Denko Co., Ltd.) are applied to the light reflecting film so that the shape is fixed. Pasted.

When a light reflecting film was incorporated into the backlight and a 2 mm thick transparent acrylic plate (total light transmittance of 90%) was installed instead of the diffusion film, the streak visibility was ◎, but the degree of uniformity could not be calculated. The average front luminance was 4200 cd / m ² .

  The planar light emitter of the present invention is suitable and useful for a surface light source used in a display device such as a personal computer, a television or a mobile phone, particularly a flat display device such as a liquid crystal display device.

It is a perspective view for illustrating and explaining the structure of a planar light emitter. It is a bird's-eye view for illustrating and explaining a linear light source structure. It is a bird's-eye view for illustrating and explaining a linear light source structure. It is a bird's-eye view for illustrating and explaining a linear light source structure. It is a perspective view for demonstrating the structure of the light reflection film which has a continuous shape comprised from a mountain-shaped part and a bottom face part. It is sectional drawing for demonstrating the structure of the light reflection film which has a continuous shape comprised from a mountain-shaped part and a bottom face part. It is sectional drawing for demonstrating the structure of the light reflection film which has a continuous shape comprised from a mountain-shaped part and a bottom face part. It is sectional drawing for demonstrating the structure of the light reflection film which has a continuous shape comprised from a mountain-shaped part and a bottom face part. It is sectional drawing for demonstrating the structure of the light reflection film which has a continuous shape comprised from a mountain-shaped part and a bottom face part. It is sectional drawing for demonstrating the relationship between the vertex of a round-shaped mountain-shaped part, and a vertex angle. It is sectional drawing for demonstrating illustratively the cross-sectional length TL of a bottom face part, the cross-sectional length KN of a light source, and the light source tube distance KL. It is sectional drawing for demonstrating the vertex position H of a mountain-shaped part, and the distance L of a light source center part and a reflecting plate bottom face part. It is sectional drawing for demonstrating the relationship between the distance L of a light source center part and a reflecting plate bottom face part, and an anisotropic diffusion film. It is a figure for demonstrating the relationship between the curve shown by Formula (1), and an xy coordinate. It is sectional drawing for demonstrating the distance CL between vertexes of an anisotropic diffusion film. It is sectional drawing for demonstrating illustration distance CL between the anisotropic diffusion films in case there exists a space | gap. It is sectional drawing for demonstrating film thickness FL of an anisotropic diffusion film. It is sectional drawing for demonstrating film thickness FL of an anisotropic diffusion film. It is a figure for demonstrating arrangement | positioning of the fluorescent tube used in the Example. It is explanatory drawing of arrangement | positioning of the fluorescent tube used in the Example, an anisotropic diffusion film, and a light reflection film. It is sectional drawing of the diffusion film which the cross-sectional shape of a lens pillar is comprised from the straight line, and becomes a prism lens pillar.

Explanation of symbols

1: diffuser plate 2: light reflection film 3: fluorescent tube 4: light source 5: vertex of light reflection film 6: mountain portion 7: bottom surface portion 8: apex angle 9: anisotropic diffusion film 10: anisotropic having prism lens column Diffusion film

12: Apex of anisotropic diffusion film 13: Gap

Claims (6)

A planar light-emitting body having at least a light reflecting plate that satisfies the following requirement A, a light source having a plurality of linear shapes, and an anisotropic diffusion film that satisfies the following requirement B.
A is a light reflecting film in which the cross-sectional shape in the direction perpendicular to the straight line of the form of the light source is a continuous shape composed of a mountain-shaped portion and a bottom surface portion.
B An anisotropic diffusion film in which a plurality of lens columns having the following cross-sectional shape are installed on at least one surface of a substrate in parallel to the surface direction of the film.
Sectional shape: the surface portion of the lens pillars, made from the curve, and the height LB of the cross section, the lens pillars rather long than half the length LA of the bottom in contact with the substrate, and the vertex of the lens pillars between The distance CL is 200 μm or less. The planar light-emitting body according to claim 1, wherein a cross-sectional shape of the anisotropic diffusion film is a part of a substantially elliptical shape and has a relationship of the formula (1).
x2 / a2 + (y + k) 2 / b2 = 1 (1)
However, y ≧ 0, b / a> 1, b> k ≧ 0.
(Here, (x, y) represents the surface coordinates in the cross section of the lens column, the film thickness direction is the y-axis direction, and the film surface direction is the x-axis direction. Further, the lens column is in contact with the substrate. The center of the substrate is x = 0, and the contact surface with the substrate is y = 0.) The planar light-emitting body according to claim 1 or 2, wherein LB / LA of the anisotropic diffusion film is 0.75 or more. The planar light emitter according to any one of claims 1 to 3, wherein an apex angle of the chevron portion of the light reflecting film is 70 ° to 110 °. The planar light-emitting according to any one of claims 1 to 4 vertex height H of the mountain-shaped portions of the light reflection film satisfy the following Symbol relationship.
H ≧ L / 2
(However, L is the distance between the center of the linear light source and the bottom of the light reflecting film) The planar light emitter according to any one of claims 1 to 5, which is a direct backlight of a display device.

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