TWI490605B - Direct type backlight device - Google Patents

Description

Direct type backlight

The present invention relates to various display devices, and more particularly to a direct type backlight device for a liquid crystal display device.

Liquid crystal display devices are commonly used in notebook computers, mobile phones, and various uses such as televisions, monitors, and car satellite navigation systems. A backlight device as a light source is mounted in the liquid crystal display device, and light from the backlight device is passed through the liquid crystal cell and controlled to form a displayable structure. The characteristics required for this backlight device are not only used as a light source for emitting light, but also to illuminate the entire picture brightly and uniformly.

The configuration of the backlight device can be roughly classified into two types. First, it is called the side light type backlight. This is mainly applied to, for example, a notebook computer that requires thinning and miniaturization, but the basic configuration is characterized by using a light guide plate. In the case of the edge-light type backlight, a light source is disposed on the side of the light guide plate to allow light to be incident from the side surface into the light guide plate, and the light is transmitted through the entire surface while being totally reflected inside the light guide plate, and is provided by A diffusion point or the like on the back surface of the light guide plate separates a part of the light from the total reflection condition, and then collects light from the front surface of the light guide plate, thereby functioning as a backlight, that is, a surface light source. In the case of the edge type backlight, in addition to the above configuration, a plurality of optical films may be used, and the optical film may be a reflective film having a function of reflecting light leaking from the back surface of the light guide plate and then utilizing it. A diffuser that emits light in front of the light guide plate, a concentrating sheet represented by a diamond lens for improving front luminance, and a brightness enhancement film that enhances brightness on the liquid crystal panel.

The other way is called the direct type backlight. This method is suitable for use in a television that requires large-scale and high-brightness. The basic configuration is characterized in that instead of using a light guide plate, the fluorescent tubes are arranged directly in the depth of the screen, or a plurality of point light sources are arranged. The LEDs are configured in a linear configuration. By arranging a plurality of linear or partially linear fluorescent tubes or LED linear light sources in parallel in the depth of the screen, it is possible to cope with a large screen and to ensure brightness more sufficiently.

However, because it is also a feature of the fluorescent tube or LED placed in the depth of the screen, it will produce uneven brightness (bright spots) in the screen, which makes the bright spot become the point of the fluorescent tube or LED and the line. Like (later, called tube spot), it is the main reason for the deterioration of image quality.

Therefore, in the direct type backlight, in order to eliminate the tube spot, a light diffusing plate having extremely high light diffusibility is disposed on the upper side of the fluorescent tube to obtain uniformity of the screen (Patent Document 1). The light diffusing plate is a light diffusing plate composed of an acrylic resin or a polycarbonate resin in which fine particles are dispersed. By using the light diffusing plate to cancel the tube spot, the image can be uniformized, but in order to enhance the diffusion, the total light transmittance is lowered, the light utilization efficiency is deteriorated, and the light is also required to be excessively enhanced due to excessive diffusion. The direction is diffused, and as a result, the front luminance required is insufficient.

Here, a diffusion sheet is disposed on the light diffusion plate, and the diffusion sheet exhibits a condensing effect of condensing light in a front direction while diffusing light in an isotropic manner. The diffusion sheet is called a sheet of a bead sheet, and the bead sheet is formed on a substrate sheet to form a diffusion layer containing fine particles of organic crosslinked particles or the like, which is different from the light diffusion sheet in order to exhibit a certain degree. An optical film that points in the directivity of the front direction.

In addition to the above, a reflection member that reflects light emitted from the fluorescent tube or the LED toward the rear, a condensing sheet for concentrating, such as a diamond lens, and a light-emitting sheet for emitting light are emitted from the fluorescent tube or the LED. The polarizing light of the light is separated to increase the brightness of the liquid crystal panel, and the brightness enhancing film or the like is combined, and various types of sheets are combined to form a direct type backlight device.

However, in the case of the direct-type backlight for thin-type televisions that has received attention in recent years, or the purpose of reducing the consumption of electric power, the direct-type backlight of the number of fluorescent tubes to be mounted is reduced or mounted. In a direct-type backlight in which an LED having a point light source having a small amount of precious metal such as mercury has a small amount, it is easy to cause tube spots or insufficient brightness. Therefore, it is necessary to use a plurality of the aforementioned optical elements, which causes difficulty in thinning, or causes an increase in cost, and causes an increase in consumption power used in the manufacture of the optical element member, and there is a concern that the environmental burden increases.

In order to solve the above problem, a method of applying a rhombic shape having a zigzag cross section on a light diffusion plate to improve the functional integration or performance improvement of various sheets has been proposed (Patent Document 2), or processing a reflection member into The projection shape is suitable for a method of applying a diamond-shaped light diffusion plate having a zigzag cross section (Patent Document 3).

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-29091

[Patent Document 2] Japanese Laid-Open Patent Publication No. 2006-164890

[Patent Document 3] Japanese Laid-Open Patent Publication No. 2006-155926

However, in the light diffusing plate having extremely high light diffusibility as in Patent Document 1, although the tube spot can be eliminated and the uniformity of the screen is improved, the total light transmittance is not large, and high luminance is caused. Difficulties.

Further, in the method of applying a molding process to a light diffusing plate or a reflecting member as in Patent Documents 2 and 3, it is not only not ideal in terms of cost or productivity, but also difficult to achieve both uniformity and brightness. Nor has it found an effective response.

The present invention has been made in view of the background of such a prior art, and provides a direct type backlight device which can not only effectively suppress tube spots but also can be used for a display device of high brightness. That is, the present invention provides a direct type backlight device which can effectively suppress tube spots even if it is used without special processing for an optical member, and can be used for a display device of high brightness.

In order to solve the above problems, the present invention adopts the following configuration. In other words, the direct type backlight device of the present invention is provided with a reflective material, a plurality of linear light sources, and an optical element group, which satisfy the following conditions (i) to (v):

(i) the plurality of linear light sources are arranged such that the longitudinal directions of the respective linear light sources are parallel;

(ii) a haze value measured by light incident on the surface of the optical element group closest to the linear light source from the side of the linear light source according to JIS K 7136 (2000), which is 99.0% or less;

(iii) having a rhombohedron in the optical element group, the rhinge lens forming a plurality of convex shapes extending in a single direction on a surface opposite to the linear light source side, and the plurality of convex shapes having a longitudinal direction parallel And the length direction of the plurality of convex shapes is parallel to the longitudinal direction of the plurality of linear light sources;

(iv) according to JIS K 7105 (1981), the 60° gloss measured on the side of the linear light source side of the reflective material is 5 or less;

(v) satisfying a distance L between centers of adjacent linear light sources among the plurality of linear light sources, and satisfying a distance from the center of the linear light source to the optical element closest to the linear light source is H The following equation (1) has a θ of 45° ≦ θ ≦ 70°.

θ=tan ^-1 ((L/2)/H) ...the equation (1)

According to the present invention, it is possible to provide a direct type backlight device which can effectively suppress tube spots even without using a specially processed optical member, and can be used for a display device of high brightness.

The present invention is directed to the above-described problems, that is, a direct type backlight device for realizing suppression of tube spots, and a combination of optical members and optical characteristics of an optical member, which are intentionally reviewed, and a member having specific optical characteristics is used for a specific combination. Then, it was found that the above-mentioned problems can be solved in one fell swoop even if no special processing is applied to the optical member.

In the direct type backlight device of the present invention, a reflective material, a plurality of linear light sources, and an optical element group are sequentially disposed, and the direct type backlight device satisfies the following conditions (i) to (v):

(i) the plurality of linear light sources are arranged such that the longitudinal directions of the respective linear light sources are parallel;

(ii) a haze value measured by light incident on the surface of the optical element group closest to the linear light source from the side of the linear light source according to JIS K 7136 (2000), which is 99.0% or less;

(iii) having a rhombohedron in the optical element group, the rhinge lens forming a plurality of convex shapes extending in a single direction on a surface opposite to the linear light source side, and the plurality of convex shapes having a longitudinal direction parallel And the length direction of the plurality of convex shapes is parallel to the longitudinal direction of the plurality of linear light sources;

(iv) according to JIS K 7105 (1981), the 60° gloss measured on the side of the linear light source side of the reflective material is 5 or less;

(v) satisfying a distance L between centers of adjacent linear light sources among the plurality of linear light sources, and satisfying a distance from the center of the linear light source to the optical element closest to the linear light source is H The following equation (1) has a θ of 45° ≦ θ ≦ 70°.

θ=tan ^-1 ((L/2)/H) ... Equation (1)

When the above-described direct type backlight device is constructed, the reason why the tube spot can be suppressed cannot be ascertained, but the reason may be derived from the following reasons.

In other words, it is estimated that the light that has reached the reflective material side in the light emitted by the fluorescent tube or the LED is reflected and reflected until it is incident on the lens, and is diffused and reflected at a certain angle on the reflective material, and is utilized. The diffused reflected light having the angle is transmitted through the optical member having the haze value of (ii), and is diffused again, so that when it reaches the lens, it is diffused at an angle suitable for the angle ‧ collecting function of the prism It plays a role in suppressing tube spots. Hereinafter, each member will be described in detail.

In the direct type backlight device of the present invention, (i) the plurality of linear light sources are arranged such that the longitudinal directions of the respective linear light sources are parallel. The linear light source may be a linear light source, a linear portion (U-shaped tube, W-shaped tube, etc.) in the light source, a point light source arranged in a line shape, or a linear shape. There is no particular limitation on the observation of the light and dark. For example, it is preferable to arrange LEDs (white type and RGB type) of a fluorescent tube or a point light source represented by a cold cathode tube in a line shape. These directions along the line are the length direction of the linear light source.

In the direct type backlight device of the present invention, (i) the linear light sources are arranged in parallel in plural. The plurality of linear light sources may not be arranged in a close parallel manner, and may be arranged substantially in parallel so that an acute angle formed in the longitudinal direction of each of the linear light sources is 10 or less.

Further, it is preferable that the arrangement pitch of the light sources is different in the plane of the direct type backlight device. For example, in the case where it is desired to illuminate the central portion of the direct type backlight device, this can be achieved by reducing the arrangement pitch of the light sources in the central portion of the screen. In addition, at the end of the screen, since it is darkened near the frame edge of the casing, the portion can be illuminated by reducing the arrangement pitch. In this way, in order to adjust the brightness in the screen, it is preferable to use an illumination effect without illuminating the arrangement pitch of the light sources.

The direct type backlight device of the present invention requires (ii) a mist measured by light incident on the surface of the optical element group closest to the linear light source from the side of the linear light source according to JIS K 7136 (2000). The value is below 99.0%. When the haze value is more than 99.0%, it is estimated that excessive diffused light is increased, and even in a direct type backlight device that satisfies the conditions of (i), (iii), (iv), and (v), the tube spot cannot be suppressed. When the haze value is 99.0% or less, the effect of suppressing the tube spot in the direct type backlight device can be obtained, and the lower limit value is not particularly limited, but the substantially lower limit value is 0.0%. Although the smaller the haze value, the suppression effect of the tube spot tends to decrease, but there is an advantageous factor for obtaining high brightness. On the other hand, the larger the haze value, the more the tube spot suppression effect can be obtained. Favorable factors can be selected according to the requirements and requirements. In order to achieve both the suppression effect and the brightness of the tube spot, there is also a combination with other members such as a reflective material, and it is not possible to generalize, but the haze value is 97.5 to 98.5%, and the performance balance can be obtained. The direct type backlight device is highly likely and therefore preferred.

The haze value of the present invention is measured by a turbidity meter (haze meter) NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd., and measured in accordance with JIS K 7136 (2000). First, after the standard alignment of the machine is performed, the member is cut into a size of 8 cm to be incident at a right angle (within an error of ±2°) from the surface on the side of the linear light source provided in the direct type backlight device. The parallel beam is set and measured. Five samples were measured for each of the four corners and the central portion of each sample, and the average of the total of 25 points was taken as the haze value.

The reason why the effect of suppressing the tube spot can be obtained by arranging the optical member having a haze value of 99.0% or less closest to the linear light source is not yet identifiable, but it may be estimated that the reason is as follows.

In other words, it is inferred that when the light passing through the optical member disposed closest to the linear light source is incident on a diamond lens described later, the angle of incidence at the incident angle is suitable for the angle of the lens, since the haze value is 99.0%. When the value exceeds this value, the suppression effect cannot be obtained. Therefore, the haze value of the optical member to which the incident angle distribution can be applied is 99.0% or less. An optical member having a haze value of more than 99.0% and an optical member having a haze value of 99.0% or less are disposed in order from the side of the linear light source, and the effects of the present invention are not obtained. When the haze value of the optical member closest to the linear light source is 99.0% or less, any material or form may be used, and examples thereof include an acrylic resin, a polystyrene resin, a polycarbonate resin, and a primary bond. The resin having an alicyclic structure or the like contains an additive such as particles and is formed into a plate shape, a film, a flaky shape, a fiber shape, or a cloth shape. Further, a resin layer containing a configuration or a particle having a pattern shape such as a rhombus or a hemispherical shape or the like may be provided on either or both surfaces of the surface in a range that does not impair the effects of the present invention, and may have transmitted light. The layer of the polarization separation function is not particularly limited, but an optical member having a rhombic configuration is preferable in order to obtain a higher brightness and a tube spot suppressing function in a balanced manner. Specific examples of such an optical member include, for example, the Sumipex (registered trademark) RM series (manufactured by Sumitomo Chemical Co., Ltd.) and the Clarex (registered trademark) DR series (manufactured by Nitto Resin Co., Ltd.). Polylite-based resin light-diffusing sheet, Panlite (registered trademark) series (manufactured by Teijin Chemical Co., Ltd.), polystyrene-based resin light-diffusing sheet (produced by Unitech Co., Ltd.), and alicyclic resin-based light-diffusing sheet The Zeonor diffusion plate series (Opts Co., Ltd.) or the like is not particularly limited thereto.

In the direct type backlight device of the present invention, (iii) the surface of the diamond lens on the side opposite to the side of the linear light source is formed by a plurality of convex shapes extending in a single direction, and the longitudinal directions of the plurality of convex shapes are parallel, and a plurality of The longitudinal direction of the convex shape is parallel to the longitudinal direction of the plurality of linear light sources. If such a convex shape is not formed, even in a direct type backlight device that satisfies the conditions of (i), (ii), (iv), and (v), the tube spot cannot be suppressed. Here, the convex shape may be any shape, and the shape observed from a vertical cross section perpendicular to the longitudinal direction of the convex shape may be, for example, a semicircular (or reversed shape) of a lenticular lens, a sinusoidal shape, A substantially triangular shape having a substantially elliptical shape, an acute angle ‧ an obtuse angle, a apex angle of a right angle (a second equilateral triangle or a non-digonal triangle), an acute angle of any angle ‧ an obtuse angle ‧ a right angle (square, rectangle, trapezoid and this The apex portion of the substantially triangular shape is a random shape in which the shape of the rounded corner, the shape, the shape, or the size of the substantially triangular shape are irregularly arranged, but the shape is not particularly limited thereto. A plurality of such shapes are combined. Further, these convex shapes are provided so as to be laid without any gap on the surface of the sheet, that is, without a flat portion, and may be provided at regular intervals or irregularly, and are not particularly limited.

The method of providing such a convex shape is not particularly limited. For example, a method of forming a resin which is ultraviolet-cured or thermosetting on a base material sheet, molding it with a mold or the like, and ejecting the resin after melting can be suitably selected. Molding method, embossing method, and the like. The convex shape is preferably a substantially triangular shape having a vertex angle of a right angle. Specific examples thereof include a vikuiti BEF series (manufactured by 3M Company) or a mirror film HGL series (manufactured by EFUN TECHNOLOGY CO., Ltd.).

Moreover, the material of the base material sheet for the convex shape is provided, for example, polyethylene terephthalate, polyethylene naphthalate, polypropyl terephthalate, polybutylene terephthalate a polyester resin such as a formate, a cyclohexanedimethanol copolyester resin, an isophthalic acid copolyester resin, a spirodiol copolyester resin, or a mercapto copolyester resin, on the primary key and/or side The bond has a resin having an alicyclic structure, a polyolefin resin such as polyethylene, polypropylene, polymethylpentene or an alicyclic olefin copolymer resin, an acrylic resin such as polymethyl methacrylate, or polycarbonate. A thermoplastic resin such as polystyrene, polyamine, polyether, polyester decylamine, polyether ester, polyvinyl chloride, or a copolymer thereof as a component, or a mixture of such resins. Among them, in terms of mechanical strength, heat resistance, dimensional stability, copolymers with other components based on biaxially stretched polyethylene terephthalate, polyethylene naphthalate or the like A polyester resin such as a mixture or the like is preferable, but is not limited thereto.

Further, even if the convex shape is provided, if the longitudinal direction of the convex shape is not parallel to the longitudinal direction of the linear light source, even if the conditions satisfying the conditions (i), (ii), (iv), and (v) are straight down The type of backlight device still cannot suppress the tube spot. Here, it is not necessary that the longitudinal direction of the convex shape is completely parallel to the longitudinal direction of the linear light source, and the tube spot can be found as long as the acute angle formed by the longitudinal direction of the convex shape and the longitudinal direction of the linear light source is 10° or less. The inhibitory effect.

The direct type backlight device of the present invention requires (iv) a 60° gloss of 5 or less as measured on the surface of the reflective material on the linear light source side in accordance with JIS K 7105 (1981). If it is greater than 60° gloss, even in a direct type backlight device that satisfies the conditions of (i), (ii), (iv), and (v), the tube spot cannot be suppressed. Further, it is preferably 4 or less at 60° gloss, and more preferably 3 or less.

The gloss of the present invention is measured by a numerical angle gloss meter (UGv-4D) using the SUGA test mechanism in accordance with JIS K 7105 (1981) in the following procedure. The entrance angle and the acceptance angle are adjusted to 60 degrees, and the aperture is adjusted so that the light source side becomes 0.75±0.25° in the incident plane, 0.75±0.25° in the vertical plane, and the light receiving side becomes 4.4±0.1° in the incident plane, vertical. Set the gap attached to the machine by 11.7±0.2° in the plane. Secondly, standard correction is performed using a black box attached to the machine and a reference plane (black glass). Then, a sample of 10 cm squares was cut out from each of the reflecting materials, and set on the measuring device, and the sample pressing member backed with the black fluff cloth was pressed thereon without causing bending of the sample thereon. Five samples were measured for each of the reflective materials, and the average value thereof was taken as 60° gloss.

The material of the present invention is not particularly limited as long as it has a 60° gloss of 5 or less. For example, a metal or alloy plate, a metal layer or a white layer on a substrate, and a fibrous structure similar to a non-woven fabric may be mentioned. The material is formed into a sheet or a film or sheet which is formed into a white film or sheet in the presence of incompatible organic or inorganic particles in the resin, and which is formed into a white film or sheet in a resin. Wait. Among these, from the viewpoints of ease of adjustment of glossiness, uniform reflection performance of a light source having good reproducibility of LED color, brightness when incorporated in a direct type backlight device, and the like, A white film or sheet of bubbles is preferred. Examples of the method of containing bubbles in the inside include a method of generating bubbles inside the resin, a method of forming bubbles around the particles by a step of stretching or the like, or an organic or inorganic particle which is incompatible with the resin. In particular, the reflective material of the present invention is preferably as the reflectance of visible light is higher. Therefore, it is preferred to use a white film containing bubbles inside. The white film is not limited, and for example, a porous unstretched or biaxially oriented polypropylene film, a porous unstretched or extended polyethylene terephthalate film is preferably used. [0034] to [0057] of JP-A-H08-262208, JP-A-2002-90515, JP-A-2002-138150, JP-A-2002-138150 [0008] ~ [0034] and the like are disclosed in detail. Among them, the porous white biaxially-oriented polyethylene terephthalate film disclosed in Japanese Laid-Open Patent Publication No. 2002-90515, or from the viewpoint of heat resistance and reflectance, and polyethylene naphthalate The porous white biaxially-oriented polyethylene terephthalate film in which the ester is mixed and/or copolymerized is more suitable as a white film of the reflective material of the present invention for the reasons described above.

The composition of such a white film can be appropriately selected depending on the use or characteristics required for use, and is not particularly limited, but a single layer and/or a composite film of two or more layers having at least one layer or more are preferable. Further, it is preferred to contain at least one or more of bubbles, inorganic particles, and organic particles in at least one layer.

For example, a single layer of a white film of the layer A may be used, and the layer A may contain any one or more of bubbles, inorganic particles, and organic particles. In addition, as an example of the two-layer structure, for example, a white film composed of two layers of the A layer/B layer of the B layer is laminated on the A layer, and at least one of the A and B layers contains bubbles. Any one or more of inorganic particles and organic particles. Further, as an example of the three-layer structure, as described above, a white film having a three-layered three-layer structure in which an A layer/B layer/A layer or an A layer/B layer/C layer is laminated may be used, and in each layer. At least one layer contains at least one of bubbles, inorganic particles, and organic particles. In the case of a three-layer structure, it is preferable that the layer B is a layer containing bubbles from the viewpoint of productivity.

The number average particle diameter of the inorganic particles and/or organic particles contained in the white film is preferably 0.3 to 2.0 μm. As the organic particles, a resin mainly composed of a crosslinked polymer component having a high melting point is preferable, and examples thereof include a polyester resin, a polyamide resin particle such as benzoguanamine, a urethane resin, an acrylic resin, and a Acrylic resin, polyamide resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, chlorinated polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, fluorine resin, ruthenium resin particles, and the like Such as hollow particles and the like. These resins may be used singly or in combination of two or more kinds of copolymers or mixtures. In terms of light resistance of a white film, it is preferred to contain a UV absorber and a light stabilizer in the spherical particles contained therein. Further, as the inorganic particles, calcium carbonate, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide, cerium oxide, magnesium oxide, barium sulfate, zinc sulfide, calcium phosphate, vermiculite, alumina, mica, mica titanium, or the like can be used. Talc, clay, kaolin, lithium fluoride, calcium fluoride, etc.

As an example of such a white film, a white film of a single layer is exemplified by Lumirror (registered trademark) E20 (manufactured by Toray Industries, Inc.), SY64, SY70 (manufactured by SKC), and White Ref Star (registered trademark). WS-220 (manufactured by Mitsui Chemicals Co., Ltd.), etc., as a white film having a two-layer structure, a Tetoron (registered trademark) film UXZ1, UXSP (manufactured by Teijin DuPont Filmes Co., Ltd.), etc., as a three-layer white film For example, Lumirror (registered trademark) E60L, E6SL, E6SR, E6SQ, E6Z, E6Z2, E80, E80A, E80B (manufactured by Toray), Tetoron (registered trademark) film UX, UXH (Teijin DuPont Filmes) System), PL230 (Mitsubishi resin (stock) system) and so on. In addition, examples of the white sheet having a configuration other than the above-described configuration include Optilon ACR3000, ACR3020 (manufactured by DuPont Co., Ltd.), and MCPET (registered trademark) (manufactured by Furukawa Electric Co., Ltd.). If (iv) according to JIS K 7105 (1981), the 60° gloss measured on the side facing the linear light source side is 5 or less, the monomer can be used as the direct type backlight device of the present invention. When the glossiness is more than 5, the reflective material can be used after the glossiness is adjusted to 5 or less by the method described later.

When the 60° gloss of the substrate of the film or the sheet itself is more than 5, it is necessary to apply various processing to the substrate to adjust the 60° gloss to 5 or less and then use it as a reflective material. The processing method is not particularly limited, and for example, a method of forming a resin which is cured by ultraviolet curing or thermosetting, followed by molding with a mold or the like, a method of embossing, a method of sandblasting, a method of laminating, a method of coating, and a coating method can be suitably selected. Various methods, such as a method of peeling the surface layer in the structure of two or more layers.

The reflective material of the present invention is preferably a resin layer having particles on the surface of the linear light source side. By containing particles, it is easy to adjust the 60° gloss to 5 or less, and it is possible to suppress tube spots. The shape of the particles is not limited to one form, and for example, a flat shape such as a star shape, a leaf shape, or a disk shape, such as a rhombus, a square, a needle, a gold syrup, an amorphous non-spherical shape, and a spherical shape (not It must be only a true spherical shape, and the cross-sectional shape of the particles is surrounded by curved surfaces such as circular, elliptical, substantially circular, and substantially elliptical, etc., and the particles of these shapes may be porous or non-porous. Hollow matter is not particularly limited. In addition, if the particle is contained, the 60° gloss can be adjusted to 5 or less, and it can be any of an organic compound, an inorganic substance, and an inorganic compound, and is not limited to one.

A method of providing a resin layer containing particles on a surface of the reflective material on the linear light source side, and examples thereof include gravure coating, roll coating, spin coating, reverse coating, rod coating, screen printing, blade coating, and the like. Various coating methods such as air knife coating and dip coating apply a coating liquid containing particles and a binder resin to a reflective material (on-line coating) or a coating material (off-line coating) equal to completion of crystal alignment. A method of forming a coating layer, or a method of laminating a film or a sheet containing particles, or the like, but not limited thereto. Further, the surface on which the layer containing the particles is provided is not particularly limited, and the reflective material is a two-layer structure of A layer/B layer, A layer/B layer/A layer or A layer/B layer/C layer 3 In the case of a layer structure, it may be provided on either side.

Examples of the reflective material having a layer containing such particles include Lumirror (registered trademark) E6QD, E6ZD (manufactured by Toray Industries, Ltd.), DR240T, RE240T (manufactured by ETERNAL CHEMICAL CO., Ltd.), and the like.

When used in a direct type backlight device, the reflective material of the present invention may have particles contained in a reflective material or a resin layer due to light emitted from a light source, particularly a cold cathode tube or the like, particularly ultraviolet rays. Deterioration (for example, optical deterioration such as yellowing or decomposition degradation of low molecular weight, etc.). Therefore, in the resin forming the resin layer containing the particles provided on the reflective material, it is preferred to contain the ultraviolet absorber and/or the light stabilizer insofar as the effect of the present invention is not impaired.

In the present invention, the content of the particles in the resin layer of the reflective material is not particularly limited as long as the gloss of 60° is 5 or less, and depending on the type and productivity of the reflective material or the particles, Therefore, it is not limited to a certain content rate, but the content of the suppression effect of the tube spot and the balance of the brightness can be selected. In view of glossiness and productivity, it is preferably 0.2% by weight or more and 75% by weight or less based on the total amount of the resin. When the content of the particles is less than 0.2% by weight, the 60° gloss may not be 5 or less. On the other hand, when it exceeds 75% by weight, the productivity is extremely deteriorated, so it is preferable to control it to 75% by weight or less. Further, it is preferably 50% by weight or more and 75% by weight or less, and more preferably 65% by weight or more and 75% by weight or less.

In the present invention, the thickness of the resin-containing resin layer provided in the reflective material is determined depending on the type and content of the reflective material or the particles, and is preferably 0.05 to 50 μm. When the thickness of the resin layer is less than 0.05 μm, the effect of suppressing the tube spot may be impaired. Conversely, when the thickness exceeds 50 μm, it is not economically desirable. Here, the thickness of the resin layer means the total thickness of the resin layer containing particles, and when it has one or more layers, the thickness of the entire resin layer, that is, the thickness of the entire resin layer of the complex tree layer is obtained. .

The direct type backlight device of the present invention requires (v) a distance L between the centers of adjacent linear light sources among the plurality of linear light sources, and from the center of the linear light source to the optical element closest to the linear light source When the distance is H, the θ satisfying the following formula (1) is 45° ≦ θ ≦ 70°.

θ=tan ^-1 ((L/2)/H) Equation (1)

Further, it is preferable that the θ which is configured to satisfy the formula (1) is 50° ≦ θ ≦ 70°, and particularly, it is particularly preferable that the θ which is configured to satisfy the formula (1) is 60° ≦ θ ≦ 70°.

Here, the case where θ is increased means that the distance between the linear light source and the optical member closest to the linear light source is the smallest, or the distance between the linear light sources is increased. The direct type backlight device which has a tendency to reduce the number of fluorescent tubes to be mounted for the purpose of reducing power consumption from the viewpoint of environmental protection tends to have the latter. It is surprising in the present invention that, in the case where the θ of the equation (1) is increased, the suppression effect of the tube spot can be further increased, that is, the direct type backlight device in which the number of the fluorescent tubes is reduced or reduced. In the middle, it can exert a greater tube spot suppression effect.

Further, it is preferable to provide a direct type backlight device in which the linear light source of the equation (1) is 45° ≦ θ ≦ 70° and satisfies H ≦ 10 mm, and the effect of suppressing the tube spot can be further enhanced.

In the direct type backlight device of the present invention, the reflective material, the plurality of linear light sources, and the optical element group are sequentially disposed, and the direct type backlight device satisfies the following conditions (i) to (v), and may be optical. The member group includes an optical member having a haze value of 99.0% or less, a rhombohedral lens, or an optical member of a film or sheet other than the above (hereinafter referred to as another optical sheet). In the optical member group, the optical member/rhombus lens/other optical sheet having a haze value of 99.0% or less and the optical member/other optical sheet having a haze value of 99.0% or less are sequentially provided from the linear light source side. /Ling lens", "optical member having a haze value of 99.0% or less, or a lens/red lens", but is not limited thereto.

As such other optical sheets, for example, a film or sheet having a function of improving light diffusibility or brightness by a layer containing particles in a substrate or a hemispherical protrusion, or by controlling light transmission can be cited. A film or sheet having a polarizing separation function, such as a polarizing property, is not limited thereto. Specific examples of such a film or sheet member include, for example, Light-Up 100 GM 2, Light-Up 100 GM 3 (manufactured by KIMOTO Co., Ltd.), UTEI, UTE II (manufactured by MN Tech Co., Ltd.), and vikuiti DBEF series (manufactured by 3M Corporation). ), etc., but is not limited to this.

The optical member, the rhombohedron, the reflective material, and the resin layer containing the particles laminated on the reflective material in the present invention can be added to the optical layer having a haze value of 99.0% or less in the range of the present invention. additive. The additive may use, for example, organic and/or inorganic microparticles, a luminescent material represented by a fluorescent whitening agent, a crosslinking agent, a flame retardant, a flame retardant auxiliary, a heat resistant stabilizer, an oxidation resistant stabilizer, an organic slip agent. , antistatic agents, nucleating agents, dyes, fillers, dispersants and coupling agents.

(Example)

Hereinafter, the measurement method and the evaluation method are shown.

(1) Haze value of the component

A turbidity meter (haze meter) NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd. was used, and measurement was carried out in accordance with JIS K 7136 (2000). The sample was cut into 8 cm squares with the member (except the reflective material) disposed closest to the linear light source of the direct type backlight. When a plurality of members are bonded by an adhesive or the like, they are immersed in an organic solvent for a sufficient period of time, and each member is peeled off without damaging the surface, and is sufficiently dried after the adhesive or the like is wiped off. The sample which is the member closest to the linear light source after being taken out is placed on the side of the linear light source when it is placed on the direct type backlight device, and is incident at a right angle (within an error of ±2°) into a parallel light beam. It is measured after setting. Five samples were measured for each of the four corners and the central portion of each sample, and the average of the total of 25 points was taken as the haze value.

(2) Whether there is a convex shape of a sheet or a shape of a convex shape

A rotary microtome made by a Japanese microtome was used to cut the sample with a blade inclination angle of 3° in a direction perpendicular to the plane of the sheet and as perpendicular as possible to the longitudinal direction of the convex shape. Then, using the scanning electron microscope ABT-32 manufactured by TOPCON Co., Ltd., the obtained cross-section of the sheet was observed so that the convex shape was reflected at a viewing magnification of 2500 times in the field of view, and the contrast of the image was appropriately adjusted to observe the shape of the convex shape. . Similarly, in the longitudinal direction of the convex shape, a total of five portions were observed at intervals of 2 to 5 cm, and it was observed whether or not a plurality of convex shapes extended substantially in one direction. When the shape of the projections could not be confirmed, the observation was performed at an observation magnification of 5000 times, and even when the observation magnification was 5,000 times, the observation magnification was 10,000 times. When it can be confirmed at any observation magnification that a plurality of convex shapes extend substantially in one direction, it is judged that it has a convex shape, and it is impossible to confirm that the plurality of convex shapes extend substantially in one direction at any observation magnification. In the case, it is judged that there is no convex shape.

(3) 60° gloss of reflective material

The digital angular angle gloss meter (UGv-4D) using the SUGA test mechanism was used in accordance with JIS K 7105 (1981), and the measurement was carried out in the following procedure. The entrance angle and the acceptance angle are adjusted to 60 degrees, and the aperture is adjusted so that the light source side becomes 0.75±0.25° in the incident plane, 0.75±0.25° in the vertical plane, and the light receiving side becomes 4.4±0.1° in the incident plane, vertical. Set the gap attached to the machine by 11.7±0.2° in the plane. Secondly, standard corrections were made using a black box attached to the machine and a reference plane (black glass). Then, a sample of 10 cm squares was cut out from each of the reflecting materials, and set on the measuring device so as to be pressed thereon by a sample pressing member to which a black flance cloth was applied without causing bending of the sample thereon. Five samples were measured for each of the reflective materials, and the average value thereof was taken as 60° gloss.

(4) Resin-containing resin layer and particle shape

Using a rotary microtome made by a Japanese Slicer Research Institute, the sample was cut in a direction perpendicular to the plane of the reflecting material with a blade inclination angle of 3°. Then, using a scanning electron microscope ABT-32 manufactured by TOPCON Co., Ltd., the cross section of the obtained reflective material was observed so that the resin layer was observed at a viewing magnification of 2500 times in the field of view, and the contrast of the image was appropriately adjusted to observe the side of the wireless light source. The resin layer, the presence or absence of particles, and the shape of the particles. When it was not possible to determine the presence or absence of the resin layer, the presence or absence of the particles, and the shape of the particles, the observation was performed at an observation magnification of 5000 times, and even when the observation magnification was 5,000 times, the observation was performed at an observation magnification of 10,000 times. When the resin layer or/and the particles are confirmed at any observation magnification, it is judged that the resin layer or/and the particles are present, and when the resin layer or/and the particles are not confirmed at any of the observation magnifications, it is judged that there is no resin. Layer or / and particles.

(5) Brightness and tube spot of the direct type backlight device

After the various members are placed in a direct type backlight (to be classified into two types) to be described later, the fluorescent lamp is turned on. One hour after lighting, a two-dimensional luminance meter CA-2000 made by Konicaminolta Sensing Co., Ltd., as shown in Fig. 1, is used from the front side of the direct type backlight device, that is, perpendicular to the direct type backlight device. Direction to measure brightness and tube spots. The measurement range is in the central portion of the direct type backlight device, and is 20 cm in the direction parallel to the fluorescent tube, and is 7 times the distance between the centers of the fluorescent tubes adjacent to the direction perpendicular to the fluorescent tube. In the horizontal direction, the longitudinal direction of the square is placed in the range of seven fluorescent tubes. The brightness and uniformity of this measurement range are then determined.

The brightness was evaluated as the average brightness of the range.

Tube plaques were obtained in the following manner. As shown in Fig. 2, nine lines (the broken line 10 in Fig. 2) of the longitudinal direction of the range are equally divided by 10 at intervals of 2 cm. Each line was used as a line of measurement for the tube spot. When the brightness is measured along the measurement line of each of the tube spots, a plurality of peaks having a higher brightness than the surrounding area and a plurality of valleys having a lower brightness than the surrounding area are observed. For one of the tube spot measurement lines, the average value of 5 points from the order of high brightness is Lmax, and the average value of 5 points from the order of low brightness is Lmin, and the average value of Lmax and Lmin is Lave. The degree of uniformity of the measurement line of the tube spot is calculated using the following formula (2). The average of the uniformity of the nine measurement lines of the tube spot was used as the tube spot. Moreover, the larger the average value, the stronger the tube spot, and the smaller the tube spot, the weaker the tube spot.

Uniformity (%) of one of the tube spot measurement lines = (Lmax - Lmin) / Lave × 100 (2)

Hereinafter, the configuration of the apparatus used in the examples and comparative examples will be described.

(1) Device 1

Size: 32 inches (725mm × 413mm, diagonal 834mm)

Diameter of the fluorescent tube: 3mm

Number of fluorescent tubes: 19

The distance between the centers of the fluorescent tubes is L: 20.4mm

Distance between the center of the fluorescent tube and the nearest optical member H: 6.5mm

The distance between the center of the fluorescent tube and the reflective material: 3.0mm

θ: 57.5° (θ=tan ^-1 ((L/2)/H))

(2) Device 2

Size: 20 inches (424mm × 331mm, diagonal 537mm)

Diameter of the fluorescent tube: 4mm

Number of fluorescent tubes: 10

The distance between the centers of the fluorescent tubes is L: 30mm

Distance between the center of the fluorescent tube and the nearest optical member H: 13mm

The distance between the center of the fluorescent tube and the reflective material: 6.0mm

θ: 49.1° (θ=tan ^-1 ((L/2)/H))

(3) Device 3

Size: 32 inches (725mm × 413mm, diagonal 834mm)

Diameter of the fluorescent tube: 3mm

Number of fluorescent tubes: 10

The distance between the centers of the fluorescent tubes is L: 40.8mm

Distance between the center of the fluorescent tube and the nearest optical member H: 9mm

The distance between the center of the fluorescent tube and the reflective material: 3.0mm

θ: 66.2° (θ=tan ^-1 ((L/2)/H))

(4) Device 4

Size: 20 inches (424mm × 331mm, diagonal 537mm)

Diameter of the fluorescent tube: 4mm

Number of fluorescent tubes: 10

The distance between the centers of the fluorescent tubes is L: 30mm

Distance between the center of the fluorescent tube and the nearest optical member H: 16mm

The distance between the center of the fluorescent tube and the reflective material: 6.0mm

θ: 41.4° (θ=tan ^-1 ((L/2)/H))

(5) Device 5

Size: 32 inches (725mm × 413mm, diagonal 834mm)

Diameter of the fluorescent tube: 3mm

Number of fluorescent tubes: 10

The distance between the centers of the fluorescent tubes is L: 40.8mm

Distance between the center of the fluorescent tube and the nearest optical member H: 6.5mm

The distance between the center of the fluorescent tube and the reflective material: 3.0mm

θ: 72.3° (θ=tan ^-1 ((L/2)/H))

Hereinafter, the members A to D used in the respective examples and comparative examples, and the order of lamination of the members will be shown.

A: Optical member closest to the fluorescent tube

(*) In the case of having a surface having a convex shape, the opposite surface of the surface is disposed toward the side of the fluorescent tube.

B: diamond lens (the positional relationship between the longitudinal direction of the convex shape on the diamond lens and the linear direction of the fluorescent tube)

(*) The opposite surface of the surface provided with the convex shape is disposed toward the side of the fluorescent tube.

C: Other optical sheets other than A and B

(*) In the case of having a concave-convex surface, the opposite surface of the surface is disposed toward the side of the fluorescent tube.

D: reflective material

(*) The glossiness shown in Table 1-1 is a value toward the surface on the side of the fluorescent tube.

Lamination sequence: The portion other than the D (reflective material) is described. A/B/C means that layers are stacked in the order of A, B, and C from the side of the fluorescent tube.

(First embodiment)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: Clarex (registered trademark) DR-III C-A DR-80C (Nitto Resin Industrial Co., Ltd.)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: None

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/B

(Second embodiment)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: Sumipex (registered trademark) RM804S (Sumitomo Chemical Co., Ltd.)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: None

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/B

(Third embodiment)

First, a 32-inch LCD TV (manufactured by Hitachi, Ltd., Wooo (registered trademark) UT32-Hv700B) is decomposed to obtain a convex shape extending in a direction opposite to the side of the fluorescent tube, and the projection A resin plate having a thickness of 2 mm which is disposed in parallel with the linear direction of the fluorescent tube in the longitudinal direction of the shape. When the light is incident from the side of the fluorescent tube at the time of mounting before the decomposition, the haze value according to JIS K 7136 (2000) is 98.3%, and then the incident surface is rotated by 90° from this state. The same measurement results were carried out, and the haze value was 98.1%.

This average value of 98.2% was taken as the haze value of the resin sheet.

Next, the resin sheet was cut into a size that can be placed on the packages 1 to 5 (hereinafter, simply referred to as a concave-convex pattern resin sheet), and the following configurations A to D were performed by the devices 1, 2, and 3. Evaluation.

A: a concave-convex resin plate (the longitudinal direction of the convex shape is set in a direction parallel to the linear direction of the fluorescent tube)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: None

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/B

(Fourth embodiment)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: Clarex (registered trademark) DR-III C-A DR-90C (Nitto Resin Industrial Co., Ltd.)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: None

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/B

(Fifth Embodiment)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: a concave-convex resin plate (the longitudinal direction of the convex shape is set in a direction parallel to the linear direction of the fluorescent tube)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: None

D: a reflective material made by the following method A

(Method A)

HALS Hybrid (registered trademark) Uv-G720T (acrylic copolymer, 40% solution, refractive index 1.56; manufactured by Nippon Shokubai Co., Ltd.): 10.0 g, ethyl acetate: 7.0 g, and Techpolymers (registered) Trademark) TRX05S (acrylic spherical particles, refractive index 1.49; manufactured by Sekisui Chemicals Co., Ltd.): 9.2 g of a coating liquid which was added while stirring. The solution was coated on the side of a white film (manufactured by Toray Industries, Inc., Lumirror (registered trademark) E6QD) composed of 188 μm porous biaxially-oriented polyethylene terephthalate, using a #16 coated rod. The coating layer was set at 120 ° C for 1 minute. The gloss of the reflective material is 5.

Stacking order: A/B

(Sixth embodiment)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: a concave-convex resin plate (the longitudinal direction of the convex shape is set in a direction parallel to the linear direction of the fluorescent tube)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: Light-Up100GM2 (made by KIMOTO); light diffusing sheet with particle-containing layer on the surface layer, haze value: 95.5%)

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/B/C

(Seventh embodiment)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: a concave-convex resin plate (the longitudinal direction of the convex shape is set in a direction parallel to the linear direction of the fluorescent tube)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: vikuiti DBEF (made by 3M company; sheet with polarized light separation function, haze value: 81.5%)

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/B/C

(Eighth embodiment)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: a concave-convex resin plate (the longitudinal direction of the convex shape is set in a direction parallel to the linear direction of the fluorescent tube)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: UTEII (manufactured by MNTech Co., Ltd.; light diffusing sheet having a hemispherical protrusion on the surface layer, haze value: 89.6%)

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/B/C

(Ninth embodiment)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: a concave-convex resin plate (the longitudinal direction of the convex shape is set in a direction parallel to the linear direction of the fluorescent tube)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C1: Light-Up100GM2 (KIMOTO); light diffuser with particle-containing layer on the surface, haze value: 95.5%

C2: vikuiti DBEF (made by 3M company; sheet with polarized light separation function, haze value: 81.5%)

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/C1/B/C2

(10th embodiment)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: a concave-convex resin plate (the longitudinal direction of the convex shape is set in a direction parallel to the linear direction of the fluorescent tube)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: Light-Up100GM2 (made by KIMOTO); light diffusing sheet with particle-containing layer on the surface layer, haze value: 95.5%)

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/C/B/C/C

(Eleventh embodiment)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: a concave-convex resin plate (the longitudinal direction of the convex shape is set in a direction parallel to the linear direction of the fluorescent tube)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: Light-Up100GM2 (made by KIMOTO); light diffusing sheet with particle-containing layer on the surface layer, haze value: 95.5%)

D: a reflective material made by the following method B

(Method B)

HALS Hybrid (registered trademark) Uv-G720T (acrylic copolymer, 40% solution, refractive index 1.56; manufactured by Nippon Shokubai Co., Ltd.): 10.0 g, ethyl acetate: 7.0 g, and Techpolymers (registered) Trademark) TRX05S (acrylic spherical particles, refractive index 1.49; manufactured by Sekisui Chemicals Co., Ltd.): 9.2 g of a coating liquid which was added while stirring. On the side of a white film (manufactured by Toray Industries, Inc., Lumirror (registered trademark) E80A) composed of 188 μm porous biaxially-oriented polyethylene terephthalate, the solution was coated with a #24 coated rod. The coating layer was set at 120 ° C for 1 minute. The gloss of the reflective material is 3.

(First comparative example)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: Clarex (registered trademark) DR-III C-A DR-90C (Nitto Resin Industrial Co., Ltd.)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: None

D: Lumirror (registered trademark) E6Sv (Dongli (share) system; thickness 225μm)

(2nd comparative example)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: Clarex (registered trademark) DR-III C-A DR-90C (Nitto Resin Industrial Co., Ltd.)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: None

D: a reflective material made by the following method C

(Method C)

HALS Hybrid (registered trademark) Uv-G720T (acrylic copolymer, 40% solution, refractive index 1.56; manufactured by Nippon Shokubai Co., Ltd.): 10.0 g, ethyl acetate: 24.1 g, and Techpolymers (registered) Trademark) TRX05S (acrylic spherical particles, refractive index 1.49; manufactured by Sekisui Chemicals Co., Ltd.): 4.0 g of a coating liquid which was added while stirring. The solution was coated on the side of a white film (manufactured by Toray Industries, Inc., Lumirror (registered trademark) E6SR) composed of a porous biaxially-oriented polyethylene terephthalate of 188 μm, using a #16 coated rod. The coating layer was set at 120 ° C for 1 minute. The gloss of the reflective material is 7.

(3rd comparative example)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: a concave-convex resin plate (the longitudinal direction of the convex shape is set in a direction parallel to the linear direction of the fluorescent tube)

B: None

C: None

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

(4th comparative example)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: a concave-convex resin plate (the longitudinal direction of the convex shape is set in a direction parallel to the linear direction of the fluorescent tube)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in the orthogonal direction)

C: None

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

(Fifth Comparative Example)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: Clarex (registered trademark) DR-III C-A DR-70C (Nitto Resin Industrial Co., Ltd.)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C: UTEII (manufactured by MNTech Co., Ltd.; light diffusing sheet having a hemispherical protrusion on the surface layer, haze value: 89.6%)

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/C/B

(Sixth comparative example)

The configurations of the following A to D were evaluated by the devices 1, 2 and 3.

A: Clarex (registered trademark) DR-III C-A DR-70C (Nitto Resin Industrial Co., Ltd.)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C1: Light-Up100GM2 (KIMOTO); light diffuser with particle-containing layer on the surface, haze value: 95.5%

C2: vikuiti DBEF (made by 3M company; sheet with polarized light separation function, haze value: 81.5%)

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/C1/B/C2

(Seventh comparative example)

The configurations of the following A to D were evaluated by the devices 4 and 5.

A: Clarex (registered trademark) DR-III C-ADR-70C (Nitto Resin Industrial Co., Ltd.)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C1: Light-Up100GM2 (KIMOTO); light diffuser with particle-containing layer on the surface, haze value: 95.5%

C2: vikuiti DBEF (made by 3M company; sheet with polarized light separation function, haze value: 81.5%)

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/C1/B/C2

(8th comparative example)

The configurations of the following A to D were evaluated by the devices 4 and 5.

A: Clarex (registered trademark) DR-III C-A DR-70C (Nitto Resin Industrial Co., Ltd.)

B: vikuiti BEFIII 90/50T (made by 3M company; convex shape: triangle with a right angle at the right angle; distance between convex shapes: 50 μm) (set in parallel direction)

C1: Light-Up100GM2 (KIMOTO); light diffuser with particle-containing layer on the surface, haze value: 95.5%

C2: vikuiti DBEF (made by 3M company; sheet with polarized light separation function, haze value: 81.5%)

D: Lumirror (registered trademark) E6QD (Dongli (share) system; thickness 188μm)

Stacking order: A/C1/B/C2

The characteristics of the examples and comparative examples are shown in Table 1-1 to Table 2-2 below.

In any of the first to eleventh embodiments, the suppression effect of the tube spot was found. When the haze value of the optical member closest to the fluorescent tube is combined with the value of the glossiness of the fluorescent tube side of the reflective material within an appropriate range, the tube spot can be suppressed even without laminating other optical members. Further, a configuration of a direct-lit backlight device having high luminance can be obtained (third embodiment).

In addition, by controlling the haze value of the optical member closest to the fluorescent tube, the balance between the suppression effect of the tube spot and the brightness can be changed, and a configuration that can cope with various requirements or uses can be proposed (first, second, second 4 examples). Further, by using a lower-gloss reflective material, the tube spot can be further suppressed (comparison between the fifth embodiment and the second embodiment, and the sixth embodiment and the eleventh embodiment). Further, by stacking other optical members, the tube spots can be further suppressed, and the order of lamination can be arbitrarily selected. Therefore, various options for the configuration of the direct type backlight device can be obtained (fifth to eleventh embodiments). Moreover, it is surprising that in almost all configurations, the devices 1 and 3 which are similar to the direct type backlights in which the tube spots are easily formed and are thinner or further reduced in the number of fluorescent tubes to be mounted are more active than the devices 2 The tube spot is suppressed, and it is not only a direct type backlight device, but as a result, it can be applied to various uses of the machine using the module. In particular, in the device 3 having a large θ angle, the tube spot is good.

On the other hand, when the glossiness of the reflective material is more than 5, the tube spot suppressing effect of the direct type backlight device is insufficient even if other members are preferable (comparison of the fourth embodiment and the first comparative example, the first Comparison of the examples with the second comparative example). Further, even if each member is selected to have a preferable value or a state of the member, the tube spot is deteriorated in the case where the longitudinal direction of the convex shape of the rhombohedron is not parallel to the longitudinal direction of the fluorescent tube (third embodiment and Comparison of the fourth comparative example). When the haze value of the optical member closest to the fluorescent tube is larger than a specific range, the tube spot suppression effect is insufficient even if a plurality of layers of other optical members are laminated (comparison between the ninth embodiment and the sixth comparative example). Further, when the haze value of the optical member closest to the fluorescent tube is larger than a specific range, even if there is another optical member having a haze value of 99.0% or less between the optical member closest to the fluorescent tube and the lens, the tube spot The suppression effect was still insufficient (the fifth and sixth comparative examples). In particular, in the case where the rhombohedron is not disposed, the tube spot is apparent (comparison between the third embodiment and the third comparative example).

Further, when the distance between the centers of the adjacent linear light sources is L, and the distance from the center of the linear light source to the optical element closest to the linear light source is H, the following equation (1) is satisfied. When θ is lower than 45° or θ is greater than 70°, tube spots are apparently formed even if other members are preferable (comparison between the third embodiment and the seventh comparative example).

θ=tan ^-1 ((L/2)/H)...the formula (1)

Further, when θ is lower than 45° or θ is larger than 70°, the tube spot suppression effect is insufficient even when other optical members are provided (comparison between the fifth embodiment and the eighth comparative example).

(industrial availability)

The direct type backlight device of the present invention can be applied not only to a liquid crystal display or a liquid crystal television, but also to various surface light sources or illumination devices.

1. . . Fluorescent tube (linear light source)

2. . . Optical member closest to the configuration of the fluorescent tube (linear light source)

3. . . Diamond lens

4. . . Cross-sectional illustration of a convex shape arranged in parallel with the longitudinal direction of the fluorescent tube (linear light source)

5. . . Reflective material

6. . . Other optical components laminated under the lens

7. . . Other optical components laminated above the lens

8. . . Luminance meter

9. . . Measuring range of tube spot and brightness

10. . . Tube spot measurement line

Fig. 1 is a cross-sectional view showing a direct type backlight device of the present invention.

Fig. 2 is a schematic view showing an upper portion of a direct type backlight device for tube spot and brightness evaluation of the present invention.

Claims (3)

A direct type backlight device is provided with a reflective material, a plurality of linear light sources and an optical component group in sequence, wherein the direct type backlight device satisfies the following conditions (i) to (v): (i) the plural The linear light sources are arranged such that the longitudinal directions of the respective linear light sources are parallel; (ii) the optical element closest to the linear light source from the linear light source side of the optical element group according to JIS K 7136 (2000) The haze value measured by the incident light is 99.0% or less; (iii) having a rhombohedron in the optical element group, the rhinge lens forming a single direction on a surface opposite to the linear light source side a plurality of extended convex shapes, the longitudinal direction of the plurality of convex shapes being parallel, and the longitudinal direction of the plurality of convex shapes being parallel to the longitudinal direction of the plurality of linear light sources; (iv) according to JIS K 7105 (1981) The 60° gloss measured on the surface of the reflective material on the linear light source side is 5 or less, and the reflective material is the following (1) or (2): (1) having the surface of the linear light source side a resin layer containing particles, (2) a white film having bubbles inside the resin; (v) the plurality of linear lines The distance between the centers of the adjacent linear light sources in the source is L, and when the distance from the center of the linear light source to the optical element closest to the linear light source is H, the following equation (1) is satisfied. θ is 45° ≦ θ ≦ 70°, θ = tan ^-1 ((L/2) / H)... Equation (1). The direct type backlight device of claim 1, wherein the reflective material is a white film of a layer of A layer/B layer/A layer or A layer/B layer/C layer, the B layer is resin Contains bubbles inside. A direct type backlight device according to claim 1 or 2, wherein the distance H is H ≦ 10 mm.