KR20090020504A - Surface light-emitting device and liquid crystal display system - Google Patents

Abstract

A surface light emitting device and a liquid crystal display device are provided to prevent non-uniformity of brightness by uniformizing brightness distribution in all directions. A plurality of light sources(12) are arranged on the same plane. A brightness distribution forming layer(18) suppressing the brightness variation of the light outputted from the plurality of light sources and having transmissibility is formed in an optical element(15). A reflective surface reflects the light outputted from the plurality of light sources and is positioned through an air layer between the optical elements while interposing the light sources.

Description

Surface light emitting device and liquid crystal display device {SURFACE LIGHT-EMITTING DEVICE AND LIQUID CRYSTAL DISPLAY SYSTEM}

The present invention relates to the technical field of the surface light emitting device and the liquid crystal display device. Specifically, the present invention relates to the technical field of suppressing luminance unevenness in a state viewed from all directions by causing the front luminance at a predetermined position between light sources to be a minimum value in a predetermined range.

Background Art Conventionally, a liquid crystal display device having a backlight (surface light emitting device) has been used as a display device such as a word processor or a laptop personal computer. As the surface light emitting device for such a liquid crystal display device, due to the request for reduction in weight and thickness, a linear light source such as a fluorescent tube is disposed on the side of the transparent plate (light guide plate), and the liquid crystal display panel is placed on the light guide plate. The edge light type backlight which arrange | positioned was mainstream.

However, with the recent increase in the size of liquid crystal display devices such as television applications, the edge light type backlight is often insufficient in brightness, and directly underneath the linear light source disposed directly below the liquid crystal display panel. Type backlight has become versatile.

45 is a perspective view illustrating a schematic configuration of a conventional direct type backlight device 1. The backlight device 1 includes light sources (linear light sources) 2, 2,..., A fluorescent tube, a reflecting plate 3, and a diffusion plate 4.

As the light source (linear light source) 2, 2, ..., for example, a cold cathode fluorescent tube (CCFL) or the like is used, and has a cylindrical shape extending in a predetermined direction. Formed.

The reflecting plate 3 is disposed in order to reuse the light reflected by the diffusing plate 4 or the like and the light not reaching the diffuser plate 4 from the light sources 2, 2,...

The diffuser plate 4 is an optical element having a thickness of at least 1 mm or more that enhances the diffusibility and the scattering property by randomly containing a resin body having a refractive index different from that of the transparent base material in the transparent base material. It is used as an optical element which suppresses the variation of a luminance distribution.

In the backlight device 1, the reflecting plate 3 and the diffuser plate 4 are arrange | positioned on the opposite side, respectively, with light sources 2, 2, ... in between.

In such a backlight device 1, the light emitted from the light sources 2, 2,... Is emitted from the diffusion plate 4, but the distance between the light sources 2, 2,... Is shortened or the distance between the light sources 2, 2, ... becomes long, the luminance of the irradiation light flux of the backlight device 1 is shown in FIG. …) It is high in the position immediately above, it becomes low in the position between the light sources 2, 2, ..., and uniformity of front luminance distribution falls, and a luminance deviation arises.

In order to suppress such a luminance deviation, as shown in FIG. 47, it is known to arrange | position optical elements 5, such as a prism sheet and a wrench circular lens sheet, instead of the diffuser plate 4 (for example, patent Documents 1 to 4). FIG. 47 shows an example in which the optical element (prism sheet) 5 is disposed in place of the diffusion plate 4 in FIG. 46.

The optical element (prism sheet) 5 has a plurality of linear projections (for example, triangular), which are continuously arranged at equal pitch on the front surface or the back surface thereof, and is generally used as a brightness enhancement sheet. It is an optical element used for. These linear projections function as the luminance distribution forming layer 5a which suppresses the luminance deviation in the optical axis direction of the light emitted from the light sources 2, 2,...

The optical element 5 is arrange | positioned so that the ridgeline direction of the linear protrusion which functions as the luminance distribution forming layer 5a may coincide with the longitudinal direction of the light source 2, 2, ... By using the optical element 5, as shown in FIG. 47, the irradiated light beam which light-out is divided into several as divided image 2A, 2A, ... of a light source, and a front-surface brightness deviation is suppressed. . In addition, FIG. 47 shows an example in which the divided images 2A, 2A, ... of the light source are increased twice as much as the light sources 2, 2, ... by the optical element 5.

[Patent Document 1] Japanese Patent Application Laid-Open No. 5-333333

[Patent Document 2] Japanese Unexamined Patent Publication No. 6-250178

[Patent Document 3] Japanese Patent Application Laid-Open No. 10-283818

[Patent Document 4] Japanese Patent Application Laid-Open No. 2004-6256

By the way, in the surface light-emitting device 1 shown in FIG. 47, as shown in FIG. 48, the dispersion | variation in the brightness (front brightness) in the state seen from the front is suppressed, but in the state seen from the inclination (bevel direction), There arises a problem that a luminance deviation occurs, causing unevenness in the luminance distribution. FIG. 48 shows an example using a prism sheet having a luminance distribution forming layer in which a plurality of hexagonal structural portions (linear protrusions) are provided, for example, as the optical element 5. The luminance distribution (hereinafter, referred to as "tilt luminance distribution") in the state seen from the inclination of becomes uneven.

In order to eliminate such unevenness of the gradient luminance distribution, for example, a plurality of diffusion sheets are stacked and disposed on the prism sheet, but in this method, a plurality of diffusion sheets are stacked, so that the luminance of light emitted from the light source is overlapped. There is a problem such as a large loss.

In addition, in order to eliminate the unevenness of the gradient luminance distribution, for example, as shown in FIG. 49, there is a method of using the diffusion sheet 6 having a high diffusion function, but in this method, a diffusion sheet having a high diffusion function ( Since 6) averages the angular distribution of the irradiation light beam emitted from the optical element (prism sheet) 5, as shown in FIG. 50, the nonuniformity of the gradient luminance distribution is improved, but the uniformity of the front luminance distribution is improved. This falls.

Then, the surface light-emitting device and liquid crystal display device of this invention overcome the above-mentioned problem, and make it a subject to suppress a luminance nonuniformity in the state seen from all directions.

In order to solve the above-mentioned problems, the surface light emitting device includes: a plurality of light sources arranged on the same plane, an optical element having a light transmitting property and a luminance distribution forming layer for suppressing a luminance deviation of light emitted from the plurality of light sources; A reflective surface positioned between the optical elements on the opposite side of the optical element via the air layer and reflecting light emitted from the plurality of light sources, and the optical element interposed therebetween; Diffusion means for diffusing light emitted from the plurality of light sources while being located on the opposite side of the plurality of light sources is provided, and the distance between each center of the light sources positioned adjacent to each other is set as the distance between the light sources, The distance in the optical axis direction from the center to the optical element is taken as the optical axis direction distance H, and the The distance in the direction toward the light sources positioned adjacent to each other from the light source is a moving distance x, and the front luminance on the optical element is? For the light emitted from the light source and passed through the optical element. When the maximum value in the front luminance φ on the optical element is φ _max , the front luminance φ at x = L / 2 takes the minimum value φ ₀ in the range where L / H is 1.8 or more and 2.3 or less, and 0.65 ? _Max ??? ₀ ? 0.85?? _Max is satisfied.

Another surface light emitting device includes an optical element having a plurality of light sources disposed on the same plane, a luminance distribution forming layer that has a light transmitting property and suppresses a luminance deviation of light emitted from the plurality of light sources in order to solve the above problems; And a reflective surface positioned between the optical elements with the plurality of light sources interposed therebetween via the air layer and reflecting light emitted from the plurality of light sources, and the optical element therebetween. Diffusion means for dispersing light emitted from the plurality of light sources while being located on the opposite side of the plurality of light sources is provided, and the distance between each center of the light sources positioned adjacent to each other is a distance L between the light sources, and the light source The distance in the optical axis direction from the center of the optical element to the optical element is taken as the optical axis direction distance H, and the light The distance in the direction from the light source to the light sources positioned adjacent to each other from each other to be a moving distance x, and the front luminance on the optical element is? For the light emitted from the light source and passed through the optical element, and the optical element When the maximum value in the said front luminance φ is made into phi _max , in the range whose L / H is 2.8 or more and 4.2 or less, front luminance φ in x = L / 2 takes the minimum value phi ₀ , and at x = 0 The front luminance φ takes the minimum value φ ₁ , and satisfies 0.65 · φ _max ≦ φ ₀ ≦ 0.85 · φ _{max and} also φ ₀ <φ ₁ .

In order to solve the above problems, a liquid crystal display device includes a plurality of light sources disposed on the same plane, an optical element having a light transmitting property and a luminance distribution forming layer for suppressing a luminance variation of light emitted from the plurality of light sources; A reflective surface positioned between the optical elements on the opposite side of the optical element via the air layer and reflecting light emitted from the plurality of light sources, and the optical element interposed therebetween; Diffusion means positioned on opposite sides of the plurality of light sources and diffusing the light emitted from the plurality of light sources, and a liquid crystal panel which displays an image and is irradiated with the light emitted from the plurality of light sources and is adjacent to each other. The distance between each center of the said light source located is made into the distance L between light sources, and from the center of the light source The distance in the optical axis direction to the optical element is taken as the optical axis direction distance H, and the distance in the direction from the light source to the light sources positioned adjacent to each other is a moving distance x, and is emitted from the light source to emit the optical element. In the range where L / H is 1.8 or more and 2.3 or less, when the front luminance on the optical element is φ and the maximum value in the front luminance φ on the optical element is φ _max for the light passing through The front luminance phi at = L / 2 takes the minimum value phi ₀ , and satisfies 0.65 占 φ _max ≤ φ ₀ ≤ 0.85 占 φ _max .

Another liquid crystal display device includes an optical element having a plurality of light sources arranged on the same plane, a luminance distribution forming layer which has a light transmitting property and suppresses a luminance deviation of light emitted from the plurality of light sources in order to solve the above problems; And a reflective surface positioned between the optical elements with the plurality of light sources interposed therebetween via the air layer and reflecting light emitted from the plurality of light sources, and the optical element therebetween. Diffusion means positioned on opposite sides of the plurality of light sources and diffusing light emitted from the plurality of light sources, and a liquid crystal panel which displays an image and is irradiated with light emitted from the plurality of light sources and is adjacent to each other. The distance between the centers of the light sources positioned so as to be the distance L between the light sources, and to the center of the light source The distance in the optical axis direction from the light source to the optical element as the optical axis direction distance H, and the distance in the direction from the light source toward the light sources positioned adjacent to each other as the movement distance x, and exit from the light source to provide the optical When the front luminance on the optical element is φ and the maximum value in the front luminance φ on the optical element is φ _max for the light passing through the element, in the range of L / H of 2.8 or more and 4.2 or less, The front luminance φ at x = L / 2 takes the minimum value φ ₀ , the front luminance φ at x = 0 takes the minimum value φ ₁ , and 0.65 · φ _max ≦ φ ₀ ≦ 0.85 · φ _max and φ ₀ <φ ₁ It is to satisfy.

Therefore, in the surface light emitting device and the liquid crystal display device, the maximum value of the luminance and the minimum value of the front luminance in the state seen from the inclination exist at approximately the same position in the moving distance from the light source.

Another surface light emitting device includes an optical element having a plurality of light sources arranged on the same plane and a luminance distribution forming layer that has a light transmitting property and suppresses a luminance deviation of light emitted from the plurality of light sources in order to solve the above problems. And a reflection surface positioned between the optical elements on the opposite side of the optical element with the plurality of light sources interposed therebetween via an air layer and reflecting light emitted from the plurality of light sources, and the optical element therebetween. A diffusing means for dispersing light emitted from the plurality of light sources while being located on the opposite side of the plurality of light sources, and protruding the luminance distribution forming layer of the optical element in the optical axis direction of the light emitted from the light source; A plurality of light sources arranged so as to be arranged in an array direction The distance between each center of the said light sources which are comprised by the structural part and located adjacent each other is made into the distance L between light sources, and the distance in the said optical axis direction from the center of the said light source to the said optical element is made into the optical axis direction distance H. And a distance in the direction from the light source to the light sources positioned adjacent to each other as a moving distance x, and a cross-sectional shape in the stretching direction of the structural portion of the luminance distribution forming layer. In the range where L / H is 2.8 or more and less than 3.5, the angle formed between the tangent contacting the outer surface of the structural part and the plane perpendicular to the optical axis is 2.8 or more and less than 3.5. The ratio of the arrangement direction components of the structural section cross-sectional shape of the outer surface portion is equal to the arrangement direction components of the structural section cross-sectional shape of the outer surface of the structural section cross-sectional shape. By a ratio (比率) of the portion Q having a tangential angle ψ is in a range from 39 ° 59 °, to one so as to satisfy the 0.37≤Q≤0.70.

Another liquid crystal display device includes an optical element having a plurality of light sources disposed on the same plane and a luminance distribution forming layer for suppressing luminance variations of light emitted from the plurality of light sources while having a light transmitting property in order to solve the above problems. And a reflection surface positioned between the optical elements on the opposite side of the optical element with the plurality of light sources interposed therebetween via an air layer and reflecting light emitted from the plurality of light sources, and the optical element therebetween. And diffusion means for diffusing the light emitted from the plurality of light sources while being located on the opposite side of the plurality of light sources, and a liquid crystal panel for displaying an image and irradiating light emitted from the plurality of light sources. Projecting the luminance distribution forming layer of the optical element in the optical axis direction of the light emitted from the light source; It is comprised by the several structure part provided so that it may line up in the arrangement direction of the said several light source, The distance between each center of the said light source located adjacent to each other shall be the distance L between light sources, and from the center of the said light source to the said optical element. The distance in the optical axis direction of is taken as the optical axis direction distance H, and the distance in the direction from the light source toward the light sources positioned adjacent to each other is the moving distance x, and in the stretching direction of the structural part of the luminance distribution forming layer. In the cross-sectional shape, when the angle formed between the tangent contacting the outer surface of the structural part and the plane perpendicular to the optical axis is the tangential angle ψ, the cross section of the structural part in the stretching direction of the structural part in the range of L / H of 2.8 or more and less than 3.5. The ratio of the arrangement direction components of the structural section cross-sectional shape of the outer surface portion of the shape is the structure of the outer surface of the structural section cross-sectional shape. The ratio with respect to array direction component of a cross-sectional shape having a tangent line angle ψ is less than 59 ° more than 39 ° portions Q, to one so as to satisfy the 0.37≤Q≤0.70.

Therefore, in another surface light emitting device and a liquid crystal display device, the local maximum value and the local minimum value of luminance in the state viewed from the inclination exist at approximately the same position in the moving distance from the light source.

The surface light-emitting device of the present invention comprises a plurality of light sources disposed on the same plane, an optical element having a light transmitting property and a luminance distribution forming layer for suppressing the luminance variation of the light emitted from the plurality of light sources, and the plurality of light sources. A reflective surface positioned between the optical element on the opposite side of the optical element via an air layer and reflecting light emitted from the plurality of light sources, and an opposite side of the plurality of light sources with the optical element therebetween A diffusing means for diffusing the light emitted from the plurality of light sources and positioned at the same time; and a distance between each center of the light sources positioned adjacent to each other as a distance between light sources, and from the center of the light source The distance in the optical axis direction up to is the optical axis direction distance H, and adjacent to each other from the light source The distance in the direction toward the light source is set as the moving distance x, and the front luminance on the optical element is? For the light emitted from the light source and passed through the optical element, and the front on the optical element. When the maximum value at the luminance φ is φ _max , the front luminance φ at x = L / 2 takes the minimum value φ ₀ in the range of L / H of 1.8 to 2.3 or less, and 0.65 · φ _max ≤ φ ₀ ≤ 0.85 It is characterized by satisfy | filling phi _max .

Therefore, the luminance distribution becomes substantially constant when viewed from all angles, and luminance unevenness can be suppressed in the state seen from all directions.

Another surface light emitting device of the present invention includes a plurality of light sources disposed on the same plane, an optical element having a light transmitting property and a luminance distribution forming layer for suppressing a luminance variation of light emitted from the plurality of light sources, and the plurality of light sources. A plurality of light sources with a reflecting surface positioned between the optical elements on the opposite side of the optical element with an air gap therebetween and reflecting light emitted from the plurality of light sources; A diffusing means for diffusing the light emitted from the plurality of light sources and positioned on the opposite side of the light source; wherein the distance between each center of the light sources positioned adjacent to each other is a distance L between the light sources, and from the center of the light source The distance in the optical axis direction to the optical element is taken as the optical axis direction distance H, and is adjacent to each other from the light source. The distance in the direction toward the light source to be positioned as a moving distance x, and the front luminance on the optical element is? For the light emitted from the light source and passed through the optical element, and the When the maximum value at the front luminance φ is φ _max , the front luminance φ at x = L / 2 takes the minimum value φ ₀ in the range where L / H is 2.8 or more and 4.2 or less, and the front luminance φ at x = 0. The minimum value φ ₁ is taken, and 0.65 · φ _max ≦ φ ₀ ≦ 0.85 · φ _{max is} also satisfied to satisfy φ ₀ <φ ₁ .

Therefore, the luminance distribution becomes substantially constant when viewed from all angles, and luminance unevenness can be suppressed in the state seen from all directions.

The liquid crystal display device of the present invention comprises a plurality of light sources disposed on the same plane, an optical element having a light transmitting property and a luminance distribution forming layer for suppressing a luminance deviation of light emitted from the plurality of light sources, and the plurality of light sources. A reflective surface positioned between the optical element on the opposite side of the optical element via an air layer and reflecting light emitted from the plurality of light sources, and an opposite side of the plurality of light sources with the optical element therebetween Diffusing means for diffusing the light emitted from the plurality of light sources simultaneously with the liquid crystal panel, wherein the liquid crystal panel is irradiated with the light emitted from the plurality of light sources while displaying an image; The distance between each center is taken as the distance L between light sources, and from the center of the light source to the optical element. The distance in the optical axis direction is the optical axis direction distance H, and the distance in the direction from the light source toward the light sources positioned adjacent to each other is the moving distance x, and the light emitted from the light source passes through the optical element. When the front luminance on the optical element is φ and the maximum value at the front luminance φ on the optical element is φ _max , L / H is 1.8 to 2.3 or less, at x = L / 2. Is characterized in that the front luminance phi of? Takes the minimum value φ ₀ and satisfies 0.65 · φ _max ≦ φ ₀ ≦ 0.85 · φ _max .

Therefore, the luminance distribution becomes substantially constant when viewed from all angles, and luminance unevenness can be suppressed in the state seen from all directions.

In another liquid crystal display of the present invention, in order to solve the above problems, a plurality of light sources arranged on the same plane and a luminance distribution forming layer which has a light transmitting property and suppresses a luminance deviation of light emitted from the plurality of light sources are formed. A reflective surface positioned between the optical element and the plurality of light sources on the opposite side of the optical element via an air layer and reflecting light emitted from the plurality of light sources; A diffusion means for dispersing the light emitted from the plurality of light sources while being located on the opposite side of the plurality of light sources, and a liquid crystal panel for displaying an image and irradiating light emitted from the plurality of light sources while being interposed therebetween; And adjacent to each other, the distance between each center of the light source is the distance L between the light sources, The distance in the optical axis direction from the shim to the optical element is taken as the optical axis direction distance H, and the distance in the direction from the light source toward the light source positioned adjacent to each other is a moving distance x, and is emitted from the light source. When the light passing through the optical element is the front luminance on the optical element as φ and the maximum value in the front luminance φ on the optical element is φ _max , the L / H is in the range of 2.8 or more and 4.2 or less. , front luminance φ at x = L / 2 takes minimum value φ ₀ , front luminance φ at x = 0 takes minimum value φ ₁ , 0.65 · φ _max ≤φ ₀ ≤0.85 · φ _max and φ ₀ <φ Characterized in that ₁ is satisfied.

Therefore, the luminance distribution becomes substantially constant when viewed from all angles, and luminance unevenness can be suppressed in the state seen from all directions.

Another surface light emitting device of the present invention includes a plurality of light sources disposed on the same plane, an optical element having a light transmitting property and a luminance distribution forming layer for suppressing a luminance variation of light emitted from the plurality of light sources, and the plurality of light sources. The plurality of light sources with a reflective surface positioned between the optical elements on the opposite side of the optical element with a light source interposed therebetween and reflecting light emitted from the plurality of light sources; A diffusing means for diffusing the light emitted from the plurality of light sources and positioned on the opposite side of the light source; protruding the luminance distribution forming layer of the optical element in an optical axis direction of the light emitted from the light source and arranging the plurality of light sources Consists of a plurality of structural units arranged so as to line up with each other, The distance between each center of the said light source is made into the distance L between light sources, The distance in the optical axis direction from the center of the light source to the said optical element is made into the optical axis direction distance H, and is located adjacent to each other from the said light source. The distance in the direction toward the light source is the moving distance x, and the angle formed by the tangent contacting the outer surface of the structural part and the plane orthogonal to the optical axis in the cross-sectional shape in the stretching direction of the structural part of the luminance distribution forming layer. In the range where L / H is 2.8 or more and less than 3.5, the ratio of the arrangement direction components of the structural section cross-sectional shape of the outer surface part of the structural section cross-sectional shape in the stretching direction of the structural part is equal to the structural section cross section of the outer surface of the structural section cross-sectional shape. The ratio Q of the part having the tangential angle ψ which becomes 39 degrees or more and 59 degrees or less with respect to the arrangement direction component of a shape is 0.37 <= Q <= 0. It characterized by satisfying 70.

Therefore, the luminance distribution becomes substantially constant when viewed from all angles, and luminance unevenness can be suppressed in the state seen from all directions.

Another liquid crystal display device of the present invention includes a plurality of light sources disposed on the same plane, an optical element having a light transmitting property and a luminance distribution forming layer for suppressing a luminance variation of light emitted from the plurality of light sources, and the plurality of light sources. A plurality of reflecting surfaces positioned between the optical elements on the opposite side of the optical element via an air layer and reflecting light emitted from the plurality of light sources; Diffusing means for diffusing the light emitted from the plurality of light sources while being located on the opposite side of the light source, and a liquid crystal panel for displaying an image and irradiating light emitted from the plurality of light sources, wherein the The luminance distribution forming layer protrudes in the optical axis direction of the light emitted from the light source to double the plurality of light sources. It is comprised by the several structure part provided so that it may line up in the column direction, The distance between each center of the said light sources located adjacent to each other shall be distance L between light sources, and in the said optical axis direction from the center of the said light source to the said optical element. In the cross-sectional shape of the stretching direction of the structural part of the luminance distribution forming layer, the distance in the optical axis direction distance H and the distance in the direction from the light source toward the light sources positioned adjacent to each other are x. When the angle formed between the tangent contacting the outer surface of the structural part and the surface orthogonal to the optical axis is the tangential angle ψ, in the range where L / H is 2.8 or more and less than 3.5, the outer surface part of the structural section cross-sectional shape in the stretching direction of the structural part The ratio of the arrangement direction components of the structural section cross-section is the arrangement of the structural section cross-sectional shape of the outer surface of the structural section cross-sectional shape. And it characterized in that the ratio Q of a portion having a tangent line angle ψ is less than 59 ° more than 39 ° with respect to the component, so as to satisfy the 0.37≤Q≤0.70.

Therefore, the luminance distribution becomes substantially constant when viewed from all angles, and luminance unevenness can be suppressed in the state seen from all directions.

EMBODIMENT OF THE INVENTION Below, the best form for implementing the surface light emitting device and liquid crystal display device of this invention is demonstrated according to attached drawing.

The best mode shown below applies the surface light-emitting device of this invention to the backlight device of a liquid crystal display device. Moreover, the application range of the surface light-emitting device of this invention is not limited to the backlight device of a liquid crystal display device, but can be applied widely to the illumination device provided in another image display device.

The surface light emitting device 10 is used, for example, as a direct type backlight device for the liquid crystal display device 50 (see FIG. 1).

The surface light emitting device 10 is formed by arranging the necessary parts of the case 11, and includes a plurality of light sources (linear light sources) 12, 12,..., A reflecting plate 13, and a diffusion means 14. And an optical element (optical plate) 15 and an optical element body 16.

As the light sources 12, 12, ..., fluorescent tubes, such as a cold cathode fluorescent tube and a hot cathode fluorescent tube, are used, for example. The light sources 12, 12, ... are formed in a cylindrical shape and are disposed on the reflecting plate 13 in a state extending in the Y direction shown in FIG. The light sources 12, 12, ... are separated in the X direction shown in FIG. 1 in a parallel state between the reflecting plate 13 and the optical element 15, and are arranged at equal intervals.

Thus, in the surface light-emitting device 10, since the some light source 12, 12, ... is arrange | positioned on the reflecting plate 13 at equal intervals, and uniformity is ensured in the arrangement | positioning state, light source 12, 12,... When the light emitted from the light reaches the liquid crystal display panel described later, it is difficult to cause partial luminance unevenness depending on the arrangement state of the light sources 12, 12, ....

The surface on the side of the reflecting plate 13 that faces the light sources 12, 12, ... is formed as the reflecting surface 13a. A part of the light emitted from the light sources 12, 12, ... is reflected toward the optical element 15 at the reflecting surface 13a. As the reflecting plate 13, it should just have a property which reflects light, For example, various things, such as aluminum, PET (polyethylene terephthalate), polycarbonate, etc. can be used.

The diffusing means 14 is disposed on the opposite side of the light sources 12, 12, ... with the optical element 15 therebetween. The diffusing means 14 has a function of diffusing light incident through the optical element 15 to uniform the luminance distribution of the irradiated light flux.

As the diffusion means 14, any one can be used as long as it has a function of diffusing light with light transmitting properties such as a diffusion plate and a film-shaped diffusion sheet. As the diffusion means 14, for example, polystyrene, cycloolefin polymer, acryl, or polycarbonate is used. As the diffusion sheet, one which assists diffusion of light, for example, a filler particle coated on a PET substrate is used. do. As the diffusion means 14, only at least one of the diffusion plate and the diffusion sheet may be used, but these may be laminated and used.

A liquid crystal display panel (not shown) is disposed on the light exit surface side of the diffusion means 14.

The optical element 15 is disposed between the light sources 12, 12,... And the diffusion means 14. The optical element 15 is, for example, a prism sheet having a light transmitting property, a wrench circular lens sheet, or the like, and the luminance distribution forming layer 18 is formed integrally on the light exit surface side of the substrate 17, for example.

The base material 17 is formed of the board | plate material made from transparent synthetic resins, such as an acrylic resin, polyethylene terephthalate, polyethylene naphthalate, a polycarbonate, a styrene resin, and a styrene-methyl methacrylate copolymer resin. Moreover, although the base material 17 can also be comprised in a sheet form or a film form, the one formed by the board material with high rigidity has the bending and curvature at the time of arrange | positioning in the case 11. ), Heat deformation, and the like are difficult to occur, and are very suitable in that the distance in the Z direction between the light source 12 is difficult to change. Moreover, the thickness of the base material 17 is not specifically limited, Even if it is about the thickness of a sheet | seat or a film, what is necessary is just to ensure predetermined rigidity.

The luminance distribution forming layer 18 has a function of suppressing the luminance variation of the light emitted from the light source 12. The luminance distribution forming layer 18 is constituted by a plurality of structural portions 18a, 18a, ... in which the Y-direction shown in FIG. 1 is in the ridge direction, and the structural portions 18a, 18a, ... are predetermined in the X-direction. The pitch is provided continuously. The structural part 18a protrudes in the Z direction shown in FIG. 1, ie, the optical axis direction of the light radiate | emitted from the light source 12, and the outer surface is formed in curved shape or polygonal shape, for example. In the case where the structural portion 18a is formed in a curved shape, it is, for example, in an aspheric shape.

The arrangement pitch of the structure portions 18a, 18a, ... is not related to the arrangement pitch of the light sources 12, 12, ..., and the structure portions 18a, 18a, ... are arranged at a minute pitch.

The optical element 15 may be formed by integrally forming the luminance distribution forming layer 18 on the substrate 17, but the luminance distribution forming layer formed of the ultraviolet curable resin on the substrate 17 ( 18 may be formed by transferring or bonding the luminance distribution forming layer 18 to the substrate 17 by press molding.

The optical element body 16 is comprised by the one or several thing of various optical elements, such as a diffusion sheet, a prism sheet, a reflective polarizer, for example. When the optical element body 16 is comprised by the some optical element, these some optical element is arrange | positioned at the laminated form. The optical element body 16 is disposed on the opposite side of the optical element 15 with the diffusion means 14 therebetween.

 In the surface light emitting device 10 configured as described above, the space between the reflecting plate 13 and the optical element 15 is formed as the air layer 19.

In the surface light emitting device 10, when light is emitted from the light sources 12, 12,..., The emitted light passes through the optical element 15, the diffusing means 14, and the optical element body 16 in order to form a liquid crystal. The display panel is irradiated. A part of the light emitted at this time is reflected by the reflecting surface 13a of the reflecting plate 13 and directed to the optical element 15.

Light incident on the optical element 15 is refracted at the incident surface of the optical element 15, and is also refracted to the diffusing means 14 when exiting from the optical element 15. Light incident on the diffusing means 14 diffuses and is emitted, and reaches the liquid crystal display panel via the optical element body 16.

In FIG. 2, the path | route of the light radiate | emitted from the light sources 12, 12, ..., the positional relationship of each part, etc. are shown.

In Fig. 2, the distance between each center of the light sources 12 and 12 located adjacent to each other is the distance L between the light sources, the refractive index of the optical element 15 is n, the thickness of the optical element 15 is d1, The distance in the optical axis S direction from the center of the optical element 15 to the optical axis 15 is the optical axis direction distance H and the refractive index of the air in the air layer 19 is n ₀ and is emitted from the light source 12 to the optical element 15. Incident angle with respect to the optical axis S of incident light is shown as (theta) ₁ , and the refractive angle in the optical element 15 of the light incident on the optical element 15 is shown as (theta) ₂ .

In addition, although the magnitude | size of the structural part 18a, 18a, ... of the luminance distribution forming layer 18 with respect to the base material 17 of the optical element 15 is exaggerated in FIG. 2, in fact, the structural part 18a, 18a is shown. , ...) are extremely small with respect to the base material 17.

In addition, as shown in FIG. 3, in the cross-sectional shape of the structure portions 18a, 18a,... Of the luminance distribution forming layer 18, the tangent TL in contact with the outer surface of the structure portion 18a and the optical axis S are orthogonal to each other. The angle formed by the plane C is defined as the tangential angle ψ. At this time, as shown in FIG. 2, the direction of orthogonal to the optical axis S from the light source 12 of the divided image 12A of the light source 12 is made into the largest tangent angle a among the tangential angles (psi). The moving distance at is taken as the moving distance x. In addition, the maximum tangential angle a is usually the bottom angle of the structural portion 18a.

Using each of the above elements (parameters), the following equations (1) to (3) are established in the surface light emitting device 10.

n ₀ · sin ψ = n · sin (ψ-θ ₂ ). … (One)

n ₀ sin θ ₁ = n sin θ ₂ . … (2)

_{x = H · tanθ 1 + d1} · tanθ 2 ... … (3).

In equation (1) to equation (3) By using the, equation (1), the refractive angle θ ₂ is calculated, the equation (2) θ ₂ calculated by substituting an arbitrary tangential angle ψ in The incident angle θ ₁ is calculated by substituting, and the moving distance x is calculated by substituting the calculated incident angle θ ₁ , the refractive angle θ ₂ , the optical axis direction distance H, and the thickness d1 of the optical element into Equation (3). Therefore, the moving distance x corresponding to the tangential angle ψ is uniquely determined, and the divided images 12A of the light reaching the contact point of the luminance distribution forming layer 18 having the tangential angle ψ are adjacent to each other. X is moved toward the light source 12.

In this way, the moving distance x of the divided phase 12A is uniquely determined by the tangential angle ψ.

FIG. 4 is a graph showing the luminance distribution in a state before transmitting the diffusion means 14 when the light emitted from the light sources 12, 12, ... is transmitted through the optical element 15. FIG.

As shown in Fig. 4, the front luminance is maximal at positions immediately above the light sources 12, 12, ..., respectively, and is located at the center of the light sources 12, 12, ... adjacent to each other, that is, at x = L / 2. It is minimal. On the other hand, the luminance distribution in the state seen from the inclination 45 ° is the maximum at the center of the light sources 12, 12, ..., respectively, and is minimized at the position immediately above the light sources 12, 12, .... Incidentally, the gradient luminance distribution 45 ° tends to be maximized at the center of the light sources 12, 12, ..., respectively, in the vicinity of L / H = 2.

In addition, although the luminance distribution in the state seen from the inclination 15 degrees, the inclination 30 degrees, and the inclination 60 degrees is also shown in FIG. 4, these inclination luminance distribution is maximum at the predetermined position between light sources 12, 12, ..., respectively.

5 is a graph showing the luminance distribution after light is transmitted through the diffusing means 14. Since the diffusing means 14 has a function of averaging the angular distribution of the irradiated light beam, the front luminance distribution and the gradient luminance distribution cancel each other, thereby making the luminance distribution of both the front luminance distribution and the gradient luminance distribution uniform. have. Therefore, the luminance distribution when the liquid crystal display panel is viewed from all angles is substantially constant irrespective of the moving distance x, thereby ensuring uniformity of the luminance distribution.

In the surface light emitting device 10, as shown in FIG. 6, the front luminance distributions M, M,... Of light emitted from each light source 12, 12,... It has a substantially triangular ridge shape in which the luminance level decreases toward the position immediately above the light sources 12 and 12 located adjacent to each other. In the position between two light sources 12 and 12 located adjacent to each other, the front luminance distributions M, part of the two light sources 12 and 12 overlap each other, and the front of the whole The luminance distribution TM is the sum of the luminance level of the light emitted from one light source 12 and the luminance level of the light emitted from the other light source 12. In the position between the two light sources 12 and 12 located adjacent to each other in this manner, a part of the front luminance distributions M and M overlap each other, whereby the luminance level is raised to the level just above the light source 12. The nonuniformity of the front luminance distribution TM is corrected.

In addition, the front luminance distribution when light is emitted from the light source 12 is not limited to the above-mentioned triangle shape, for example, the outline triangular shape with rounded vertices (refer FIG. 7), It may be a shape (see FIG. 8) or the like having an end portion at an inclined portion. In addition, when the value of the ratio L / H of the distance L between light sources and the optical axis direction H is large, as shown in FIG. 9, the luminance level has the minimum value in the position immediately above the light source 12, As shown in FIG. 10, the shape may be substantially constant in the vicinity of the position immediately above the light source 12.

In the surface light emitting device 10, as described above, the front luminance is minimal at x = L / 2, which is the center of the light sources 12 and 12 positioned adjacent to each other. At this time, when the front luminance is φ, the minimum value φ ₀ of the front luminance φ satisfies the following relationship with respect to the maximum value φ _max of the front luminance φ.

0.65φ _max ≤φ ₀ ≤ 0.85φ _max ... … (4).

When x = L / 2, the front luminance φ takes the minimum value φ ₀ , and the minimum value φ ₀ satisfies the above formula (4), whereby the liquid crystal display panel is removed at all angles in a range of L / H of 1.8 to 2.3. The uniformity of the luminance distribution when viewed is ensured.

In order to establish the above equation (4), the structural portions 18a, 18a, ... in the luminance distribution forming layer 18 of the optical element 15 satisfy the following relationship in a range of L / H of 1.8 or more and 2.3 or less. It is preferable that it is formed in the shape.

35 ° + 5 ° · L / H ≦ a ≦ 50 ° + 5 ° · L / H. … (5).

In this way, the maximum tangential angle a of the structural portion 18a satisfies the above expression (5), thereby adjusting the diffusion state of the distal end portion (end portion) of the luminance distribution of the light emitted from the single light source 12. It is possible.

11 is a graph showing Equation (5). In Fig. 11, the upper segment represents a = 50 ° + 5 ° · L / H, which is the upper limit of equation (5), and the lower segment is a = 35 °, which is the lower limit of equation (5). + 5 ° · L / H is shown. Therefore, when the maximum tangential angle a is included between the upper limit and the lower limit, the front luminance φ takes the minimum value φ ₀ at x = L / 2.

In addition, in order for Formula (4) and Formula (5) to hold, it is necessary to determine the shape of the structural part 18a so that the maximum tangential angle a may become a predetermined angle, but the tangential angle ψ of the structural part 18a is an optical element. When the thickness d1 of (15) and the optical axis direction distance H are determined, it becomes a function of only the moving distance x by said Formula (1)-Formula (3).

12 shows, for example, equations (1) to (3) when the optical axis direction distance H = 15.0 mm, the thickness d1 = 1.0 mm of the optical element, the refractive index n = 1.59 of the optical element, and the refractive index n ₀ = 1.0 of air. It is a graph showing the relationship between the tangential angle ψ and the moving distance x on the basis of.

Thus, the relationship between the tangential angle ψ and the moving distance x is derived based on equations (1) to (3) by determining the optical axis direction distance H and the thickness d1 of the optical element, and the distance L between the light sources is determined to determine the equation (4). And by forming the shape of the structure parts 18a, 18a, ... so that Formula (5) may be satisfied, it becomes possible to adjust the luminance distribution of light by the tangential angle (psi), and ensure the uniformity of a luminance distribution.

In addition, when a certain tangential angle ψ occupies a large proportion in the structure portion 18a, much light is refracted at the moving distance x corresponding to the tangential angle ψ. For example, when the structure portion 18a is formed in a substantially triangular shape having a vertex angle of 90 °, the tangential angle ψ = 45 ° occupies a large proportion, and the moving distance corresponding to the tangential angle ψ = 45 °. In x, much light is refracted, and only the luminance level of the corresponding portion is increased. Therefore, when such a specific tangential angle (psi) occupies a large ratio in the structural part 18a, there exists a possibility that the front luminance (phi) may become the maximum at x = L / 2 or its vicinity.

Therefore, in the surface light emitting device 10, the outer surface of the structural section cross-sectional shape in the stretching direction of the structural portions 18a, 18a, ... so that the front luminance phi does not become maximum at x = L / 2 or its vicinity. The ratio P of the portion having the tangential angle ψ such that the ratio of the arrangement direction components of the structural section cross-sectional shape of the portion is 40 ° or more and a or less satisfies the following formula (6).

Specifically, the ratio P is set to 1 when the arrangement direction component of the entire structural part cross-sectional shape of the outer surface J of the structural section cross-sectional shape (see FIG. 2) in the stretching direction of the structural parts 18a, 18a,. It is the ratio which the part which has the tangential angle (psi) from which the ratio of the arrangement direction component of a structural part cross-sectional shape becomes 40 degrees or more and a or less.

0.15? P? 0.45... … (6).

a is a maximum tangential angle in a structural part as mentioned above.

Thus, by making ratio P into the fixed range shown by Formula (6), the local maximum of front luminance (phi) will not exist in x = L / 2 or its vicinity.

FIG. 13: is a figure which shows the example (shape examples 1-4) of the cross-sectional shape of the structural part of the luminance distribution forming layer which the luminance distribution became substantially constant regardless of the moving distance x when viewed from arbitrary angles. In FIG. 13, L / H = 2.0 and it is an example in which the diffusion means (diffusion plate) of 60% of the total light transmittance was used.

FIG. 14 is a graph showing a relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle φ or more of the tangential angle ψ according to the configuration example of FIG. 13. For example, when the structural part of the shape example 1 is considered, the tangential angle (psi) of 35 degrees or more occupies about 40% with respect to the tangential angle of the whole distribution of the said structural part. Moreover, the intersection with the X axis of each data of the shape examples 1-4 shows the maximum tangential angle a.

When the maximum tangential angle a is calculated by substituting L / H = 2.0 into the above formula (5), the value of the maximum tangential angle a becomes 45 ° or more and 60 ° or less. Therefore, about the shape example 1-the shape example 4 of FIG. 14, in all (all), the maximum tangential angle a is 45 degree or more and 60 degrees or less, and satisfy | fills said Formula (5).

Moreover, when the ratio P of the tangential angle (psi) which becomes 40 degrees or more a or less among the whole distribution of the tangential angle (psi) is calculated | required with respect to the shape examples 1 thru | or shape example 4, it exists in the range of 0.25-0.38, and the shape examples 1 thru | or the shape example 4 In any case, the above formula (6) is satisfied.

Moreover, about the shape examples 1 thru | or the shape example 4, the minimum value (phi) ₀ satisfy | fills said Formula (4) in the range of 0.65phi _max- 0.85phi _max .

15 is a figure which shows the example (shape 5-shape 11) of the cross-sectional shape of the structural part of the luminance distribution forming layer in which luminance distribution was not become substantially constant when seen from arbitrary angles. Also in FIG. 15, similarly to the example of FIG. 13, L / H is 2.0, which is an example in which a diffusion means (diffusing plate) having a total light transmittance of 60% is used.

FIG. 16 is a graph showing the relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle φ or more of the tangential angle ψ more than the tangential angle ψ, similarly to FIG. 14. The intersection with the X axis | shaft of each data of the shape examples 5-11 shows the maximum tangential angle a.

When the maximum tangential angle a is calculated by substituting L / H = 2.0 into the above formula (5), the value of the maximum tangential angle a becomes 45 ° or more and 60 ° or less. Therefore, about each shape example (shape examples 5-9, shape example 11) other than the shape example 10 of FIG. 16, neither of the maximum tangential angle a is 45 degrees or more and 60 degrees or less, and it is said Formula (5) Does not satisfy.

In addition, when the ratio P of the tangential angle ψ which becomes 40 degrees or more a below the total distribution of the tangential angle ψ is calculated | required with respect to the shape examples 5 thru | or 11, respectively, it exists in the range larger than 0 or 0.45 except for the shape example 9. In addition, about the shape examples 5, 6, 7, 8, 10, and 11, neither of the said Formula (6) is satisfied.

In addition, about the shape examples 5-11, the minimum value phi ₀ of the front luminance φ is less than 0.65φ _max at the position of x = L / 2, or the minimum value φ ₀ of the front luminance φ at the position of x = L / 2. It does not have or is larger than 0.85φ _max . Therefore, about the shape examples 5-11, neither of these satisfy | fills Formula (4).

Thus, about the example (shape examples 1 thru | or 4) which satisfy | fills said Formula (4), (5), (6), it was confirmed that luminance distribution becomes substantially constant when it sees from any angle.

FIG. 17 is a chart in which the respective data are listed with respect to Shape Examples 1 to 11 shown in FIGS. 13 to 16.

In the surface light emitting device 10, as described above, it is preferable to satisfy the above formula (5) in the range of L / H of 1.8 or more and 2.3 or less, but in the range of L / H of 2.8 or more and 4.2 or less, the following formula ( 5) 'is desirable.

35 ° + 5 ° · L / H ≦ a ≦ (the smaller angle of 50 ° + 5 ° · L / H and 65 °)... … (5) ´.

Thus, by satisfy | filling the said Formula (5) 'with the maximum tangential angle a of the structure part 18a, it is possible to adjust the diffusion state of the terminal part of the luminance distribution of the light radiate | emitted from the single light source 12. As shown in FIG.

In the above, the case where the range of L / H is a small range of 1.8 to 2.3 is explained. However, when L / H is a large range, the optical axis direction distance H, which is the distance between the light source and the optical element, becomes small or adjacent to each other. The distance L between light sources, which is the distance between them, becomes large, and the luminance at x = 0 (position immediately above the light source) tends to be larger than the luminance at x = L / 2. Therefore, in the range where L / H is large, the front luminance distribution φ has a shape as shown in FIG. 9, taking the minimum value φ ₁ at the position immediately above the light source (x = 0), and of the tangential angle ψ of the structural portion 18a. It is preferable that the value of the ratio P of the tangential angle (psi) which becomes 40 degrees or more a or less in the whole distribution is large.

Light incident from the light source perpendicularly to the lower surface of the optical element (the surface opposite to the light source) is reflected internally in the luminance distribution forming layer, but this reflection angle becomes smaller as the maximum tangent angle a becomes larger, and the luminance is increased. Light emitted from the distribution forming layer tends to be incident on the diffusion means without being incident on the adjacent luminance distribution forming layer. When light enters the diffusing means in this manner, the amount of light at x = 0 increases due to the angular averaging by the diffusing means, and even if the minimum value φ ₁ is taken at x = 0, the luminance at x = 0 becomes too large. When viewed from the angle of, the luminance distribution is less likely to be substantially constant. Therefore, in the range of 2.8 or more and 4.2 or less where L / H is large, in the formula (5) ', the upper limit of the maximum tangential angle a is 65 ° so as not to be a high angle.

When the value of the ratio P is large, a large angle increases at the tangential angle ψ of the structure portion 18a, the luminance of the divided image at a position close to x = L / 2 increases, and the luminance of the divided image at a position immediately above the light source is reduced. . For example, in the range where L / H is 2.8 or more and less than 3.5, the ratio P is 0.55 ≦ P ≦ 0.70... … (6) ´

In the range where L / H is 3.5 or more and 4.2 or less, the ratio P is

0.60? P? 0.75... … (6) ”

It is preferable to become.

However, if the value of the ratio P becomes too large, the minimum value φ ₁ of the front luminance distribution φ at the position immediately above the light source may become too small, and there is a fear that the luminance of the light after passing through the diffusion means decreases directly above the light source. Therefore, in order that the brightness of the light after passing through the diffusion means does not become too small directly above the light source, the minimum value φ ₁ of the front luminance distribution at x = 0 is larger than the minimum value φ ₀ of the front luminance distribution at x = L / 2. It is necessary.

? ₀ <? ₁ . … (7).

18 is a cross-sectional view of the structural portion of the luminance distribution forming layer in which the luminance distribution becomes substantially constant regardless of the moving distance x when viewed from any angle, for an example in which L / H is 2.8 or more and less than 3.5 and L / H = 3.0. It is a figure which shows the example (shape example 12-14) of a shape. 18 is an example in which a diffusion means (diffusion plate) having a total light transmittance of 60% is used.

FIG. 19 is a graph similar to FIG. 13 showing a relationship between the tangential angle ψ and the tangential angle of the tangential angle of the tangential angle ψ or more in relation to each configuration example according to FIG. 18.

When the maximum tangential angle a is calculated by substituting L / H = 3.0 in the above formula (5) ', the value of the maximum tangential angle a becomes 50 ° or more and 65 ° or less. Therefore, about the shape examples 12-14 of FIG. 19, the maximum tangential angle a is set to 50 degrees or more and 65 degrees or less, and satisfy | fills said Formula (5) '.

Moreover, when the ratio P of the tangential angle ψ which becomes 40 degrees or more a below the total distribution of the tangential angle (psi) is calculated | required about the shape examples 12-14, respectively, it exists in the range of 0.62-0.68, and the shape examples 12-14 In any case, the above formula (6) 'is satisfied.

Moreover, about the shape examples 12-14, the local minimum value phi ₀ of the front luminance phi in the position of x = L / 2 exists in the range of 0.65φ _max- 0.85φ _max , and both satisfy said Formula (4). Let's do it.

In addition, about the shape examples 12-14, all are phi ₀ <phi ₁ and satisfy | fill the said Formula (7).

On the other hand, FIG. 20 is an example of the cross-sectional shape of the structural portion of the luminance distribution forming layer in which the luminance distribution is not substantially constant when viewed from any angle in the case of L / H = 3.0 as an example in which L / H is 2.8 or more and less than 3.5. It is a figure which shows (shape examples 15-18). 20 is an example of the case where a diffusion means (diffusion plate) having a total light transmittance of 60% is used.

FIG. 21 is a graph showing the relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle φ or more of the tangential angle ψ, similarly to FIG. 14, for each configuration example in FIG. 20.

When the maximum tangential angle a is calculated by substituting L / H = 3.0 in the above formula (5) ', the value of the maximum tangential angle a becomes 50 ° or more and 65 ° or less. Therefore, with respect to the shape example 16 and the shape example 17 of FIG. 21, in either case, the maximum tangential angle a is 50 degrees or more and 65 degrees or less, and satisfy | fills said Formula (5) ', The maximum tangential angle a is smaller than 50 ° or larger than 65 °, and does not satisfy the above formula (5) '.

In addition, when the ratio P of the tangential angle ψ which becomes 40 degrees or more a below the total distribution of the tangential angle (psi) is calculated | required with respect to the shape examples 15-18, the shape example 15 and the shape example 18 are the said Formula (6) ' Although it satisfies, the shape example 16 and the shape example 17 do not satisfy said Formula (6) '.

In addition, the shape example 16, and would for example shape 17 which the formula (4) but a satisfactory, the shape example 15, and the shape is a minimum value φ ₀ 18 for example less than or 0.85φ 0.65φ _{max max} than the cursor the formula (4 Does not satisfy).

Thus for, the shape example 15 in addition φ ₀ is <and φ ₁ Any of φ ₀ for but satisfy the formula (7), the shape example 16, and the shape example 18> φ ₁ does not satisfy the formula (7) In addition, about the shape example 17, since it did not have (phi) ₁ , the said Formula (7) was not satisfied.

Thus, for the examples (shape examples 12 to 14) that satisfy the above formulas (4), (5) ', (6)', and (7), the luminance distribution is substantially constant when viewed from any angle. It was confirmed to be done.

FIG. 22 is a chart in which respective data are listed with respect to Shape Examples 12 to 18 shown in FIGS. 18 to 21.

FIG. 23 is a cross-sectional view of the structural portion of the luminance distribution forming layer in which L / H is 3.5 or 4.2 or less and L / H = 4.0 as an example in which L / H is 4.0. It is a figure which shows the example (shape example 19-shape 21) of a shape. Fig. 23 is an example of the case where a diffusion means (diffusion plate) having a total light transmittance of 60% is used.

FIG. 24 is a graph similar to FIG. 13 showing a relationship between the tangential angle ψ and the tangential angle of the tangential angle φ or more of the tangential angle ψ according to the configuration example of FIG. 23.

When the maximum tangential angle a is calculated by substituting L / H = 4.0 into the above formula (5) ', the value of the maximum tangential angle a becomes 55 ° or more and 65 ° or less. Therefore, about the shape examples 19-21 of FIG. 19, in either case, the maximum tangential angle a is 55 degree or more and 65 degrees or less, and satisfy | fills said Formula (5) '.

Moreover, when the ratio P of the tangential angle (psi) which becomes 40 degrees or more a below the total distribution of the tangential angle (psi) is calculated | required with respect to the shape examples 19-21, respectively, it exists in the range of 0.61-0.73, and the shape examples 19-shape 21 In any case, the above formula (6) ”is satisfied.

Moreover, about the shape examples 19-21, the minimum value phi ₀ of the front luminance phi in the position of x = L / 2 exists in the range of 0.65phi _max- 0.85phi _max , and all satisfy said formula (4). .

In addition, about the shape examples 19-21, all are phi ₀ <phi ₁ and satisfy | fill the said Formula (7).

On the other hand, FIG. 25 is an example of the cross-sectional shape of the structural part of the luminance distribution forming layer in which the luminance distribution is not substantially constant when viewed from any angle in the case where L / H is 4.0 to 4.2 or less, where L / H is 4.0. It is a figure which shows (shape examples 22-26). 25 is an example in which a diffusion means (diffusion plate) having a total light transmittance of 60% is used.

FIG. 26 is a graph showing the relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle φ or more of the tangential angle ψ more than the tangential angle φ, similar to FIG. 14.

When the maximum tangential angle a is calculated by substituting L / H = 4.0 into the above formula (5) ', the value of the maximum tangential angle a becomes 55 ° or more and 65 ° or less. Therefore, with respect to the shape example 22 and the shape example 26 of FIG. 26, in either case, the maximum tangential angle a is 55 degree or more and 65 degrees or less, and satisfy | fills said Formula (5) ', The maximum tangential angle a is less than 55 ° or larger than 65 °, and does not satisfy the above formula (5) '.

In addition, when the ratio P of the tangential angle ψ which becomes 40 degrees or more a below the total distribution of the tangential angle (psi) is calculated | required about the shape examples 22-26, the shape example 23 and the shape example 24 are the said Formula (6) " Although the shape example 22, the shape example 25, and the shape example 26 do not satisfy said Formula (6) ".

In addition, as for the shape example 22, but it satisfies the formula (4), large than the minimum value φ ₀ With respect to the shape examples 23 to the shape example 26 is smaller than or 0.85φ 0.65φ _{max max} does not satisfy the formula (4).

In addition, for the shape examples 23 to the shape example 26, phi ₀ <phi ₁ and the above formula (7) was satisfied, while for the shape example 22, phi ₀ > phi ₁ and the above formula (7) was not satisfied.

Thus, for the examples (shape examples 19 to 21) satisfying the above formulas (4), (5) ', (6) ", and (7), the luminance distribution is substantially constant when viewed from any angle. It was confirmed to be done.

FIG. 27 is a chart in which the respective data are listed for the Shape Examples 19 to 26 shown in FIGS. 23 to 26.

In the surface light emitting device 10, the total light transmittance T of the diffusion means 14 is set to 0.55 or more and 0.85 or less. The diffusing means 14 has a function of averaging the angular distribution of the irradiated light beams emitted from the light sources 12, 12, ..., and emitted from the optical element 15, but this function increases as the total light transmittance T decreases. . However, the function of averaging the total light transmittance T to about 0.55 is saturated (approximately maximized), and even if the total light transmittance T is smaller than 0.55, the averaging function hardly changes and the luminance loss increases. Moreover, as the total light transmittance T decreases from about 0.85, the averaging function of the angular distribution is remarkably exhibited. Therefore, by making the total light transmittance T of the diffusion means 14 into 0.55 or more and 0.85 or less, it is possible to fully exhibit the averaging function of the angular distribution of the diffusion means 14, suppressing a luminance deviation.

FIG. 28 is a graph showing the relationship between the occurrence rate (nonuniformity rate) and L / H of the luminance deviation when the diffusion means having different total light transmittance T is used. FIG. 29 is a graph showing an enlarged portion of the graph of FIG. 28. The horizontal axis represents the ratio L / H of the distance L between the light sources with respect to the optical axis direction distance H, and the vertical axis represents the occurrence rate (nonuniformity) of the luminance deviation.

In the data of FIGS. 28 and 29, data other than the solid line includes a light source and a diffusion means disposed on opposite sides of the optical element, and a diffusion sheet and a prism sheet on the opposite side of the optical element having the diffusion means. Data measured by the arrangement. The solid data is the data obtained by removing the optical element from this configuration. The data shown in the figure are data measured using the diffusion means whose total light transmittance T is 0.58, 0.66, 0.76, 0.79 or 0.85, respectively.

In the configuration in which the optical element is arranged, the light emitted from the light source and transmitted through the optical element to the diffusing means is diffused by the diffusing means except for a part and is emitted to the diffusion sheet and prism sheet side. A part of these outgoing light is reflected and returned to the diffusion means side, and is diffused by the diffusion means and the optical element, and then is emitted again to the diffusion sheet and prism sheet side. As shown in FIG. 28 and FIG. 29, it was confirmed that, in the case of using the optical element, the incidence of the luminance deviation was significantly lowered as compared with the case of not using the optical element.

Moreover, when using an optical element, it was confirmed that the incidence rate of a brightness | variance deviation becomes low by using the diffusing means which has the total light transmittance T shown in drawing in the range of L / H shown in drawing. In particular, it was confirmed that the incidence of the luminance deviation greatly decreased by using the diffusion means having the total light transmittance T of 0.66 to 0.85. Therefore, by making the total light transmittance T of the diffusion means 0.66 or more and 0.85 or less, it is possible to maximize the averaging function of the angular distribution of the diffusion means while suppressing the luminance variation.

When the total light transmittance T of the diffusion means becomes high, the occurrence of the luminance deviation increases from the diffusion sheet and prism sheet side to the light returning beyond the diffusion means to the light source side. It is considered that the amount of diffusion decreases due to the increase.

In the surface light emitting device, as described above, in a range where L / H is large, for example, in a range where L / H is 2.8 or more and less than 3.5, the luminance at the position immediately above the light source becomes high and luminance variation occurs. Easier Therefore, it is preferable to increase the amount of light returned to the optical element side among the light near x = 0 emitted from the optical element toward the diffusion means side. In this way, when the amount of light returned to the optical element side of the light near the x = 0 emitted from the optical element toward the diffusion means side is increased, the luminance level has a minimum value at the position immediately above the light source as shown in FIG. It is easy to be distributed.

30 is a graph showing the luminance distribution when the luminance distribution forming layer uses an optical element constituted by an isosceles triangular structure portion at L / H = 3.7, for example, and the tangent angle? This is data when a plurality of different optical elements are used. The data in FIG. 30 is data in a configuration in which a light source and a diffusion means are disposed on opposite sides of the optical element, and a diffusion sheet and a prism sheet are disposed on the opposite side of the optical element having the diffusion means.

For example, in the case of using an optical element having a tangential angle ψ of 65 °, the luminance of the light source immediately above (x = 0) is high, the luminance between the light sources is low, and the amount of light returned from the diffusion means side to the light source side. This is less. Conversely (opposite), for example, in the case of using an optical element having a tangential angle psi of 45 °, the luminance immediately above the light source (x = 0) is low, the luminance between the light sources is high, and from the diffusion means side to the light source side. There is a lot of light coming back.

As described above, in the range where L / H is large, it is preferable to increase the amount of light returned to the optical element side among the light near x = 0, and in the data of FIG. 30, the amount of light returned to the optical element side is increased. It was confirmed that the tangential angle ψ of the structural portion is preferably 39 ° or more and 59 ° or less.

Therefore, by using the optical element comprised by the structural part which has the tangential angle (psi) of 39 degrees or more and 59 degrees or less in the range of 2.8 or more and 3.5 which are L / H large range, brightness deviation can be suppressed.

FIG. 31: is a figure which shows the example (shape examples 27-31) of the cross-sectional shape of the structural part of the luminance distribution forming layer in which the luminance distribution became substantially constant regardless of the moving distance x when viewed from an arbitrary angle. In FIG. 31, L / H is set to 2.8 or more and less than 3.5, and it is an example when the diffusion means (diffusion plate) of 66% of the total light transmittance is used.

FIG. 32 is a graph showing a relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle φ or more of the tangential angle ψ according to the configuration example of FIG. 31. The ratio Q in which the tangential angle ψ is 39 ° or more and 59 ° or less with respect to the shape examples 27 to 31 is 0.44 for the shape example, 0.44 for the shape example 28, 0.37 for the shape example 29, 0.42 for the shape example 30, 0.51 for the shape example 30, and the shape example 31. Is 0.50.

In addition, similar to the ratio P described above, when the arrangement direction component of the structural section cross-sectional shape of the entire outer surface J of the structural section cross-sectional shape (see FIG. 2) in the stretching direction of the structural part is set to 1, the structural section cross section It is the ratio which the part which has the tangential angle (psi) from which the ratio of the arrangement direction component of a shape becomes 39 degrees or more and 59 degrees or less occupies for the whole outer surface J. As shown in FIG.

On the outer surface of the structural section cross-sectional shape in the stretching direction of the structural part, the arrangement direction component of the structural section cross-sectional shape among the parts other than the part having the tangential angle ψ such that the ratio of the arrangement direction components of the structural section cross-sectional shape is 39 ° or more and 59 ° or less. The ratio R is the ratio of the part having the tangential angle ψ greater than 59 °. The ratio R is 0.36 in the shape example 27, 0.59 in the shape example 28, 0.90 in the shape example 29, 0.80 in the shape example 30, and 0.86 the shape. Example 31 is 1.00.

FIG. 33: is a figure which shows the example (shape examples 31-33) of the cross-sectional shape of the structural part of the luminance distribution forming layer by which the luminance distribution became substantially constant regardless of the moving distance x when viewed from an arbitrary angle. Also in FIG. 33, L / H is 2.8 or more and less than 3.5 similarly to each shape example shown in FIG. 31, and it is an example when the diffusion means (diffusion plate) of 66% of the total light transmittance is used. In addition, although the shape example 31 shown in FIG. 33 is an example similar to the shape example 31 shown in FIG. 31, it is shown for the comparison with the shape example 32. As shown in FIG.

FIG. 34 is a graph showing a relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle φ or more of the tangential angle ψ to the shape example 32 and the shape example 33 in FIG. 33. As for the ratio Q in which the tangential angle (psi) is 39 degrees or more and 59 degrees or less with respect to the shape example 32 and the shape example 33, the shape example 32 is 0.63 and the shape example 33 is 0.50.

As for the ratio R, the shape example 32 is 0% and the shape example 33 is 100%.

35 is a ratio Q in which the tangential angle ψ is 39 ° or more and 59 ° or less with respect to the other shape examples 3, 5, 8, 9, 11 to 14, and 16 to 25 described above in addition to the shape examples 27 to 33. And a table showing the occurrence of luminance deviation. As shown in FIG. 35, although the luminance deviation of the shape example whose ratio Q is 0.37-0.68 is low, it was confirmed that the luminance deviation of the shape example whose ratio Q is less than 0.37 or 0.72 or more becomes high.

Therefore, in the range where L / H is 2.8 or more and less than 3.5, the tangential angle ψ in which the ratio of the arrangement direction components of the structural section cross-sectional shape of the outer surface portion of the structural section cross-sectional shape in the stretching direction of the structural part becomes 39 ° or more and 59 ° or less. When the ratio Q of the part to have satisfy | fills 0.37 <= Q <= 0.70, brightness deviation can be suppressed.

36 is a graph showing, for example, the luminance distributions of the shape example 31 and the shape example 32 in comparison. In the shape example 31, the ratio Q was 0.50, but the ratio R was 1.00, and in the shape example 32, the ratio Q was 0.63 but the ratio R was 0, and the ratio R of the configuration example 31 was larger than the ratio R in the configuration example 32.

36, V, V,... As shown by the figure, the luminance distribution of the shape example 31 has a moderate degree of increase in the luminance immediately next to the light source with respect to the brightness just above the light source (x = 0). In the luminance distribution, the degree of increase in luminance immediately next to the light source with respect to the luminance immediately above the light source (x = 0) is urgent. Therefore, as described above, it is possible to suppress the luminance deviation by setting the range of the ratio Q to 0.37 or more and 0.70 or less. However, in order to further reduce the contrast near the light source and to further suppress the luminance variation, It is preferable that ratio R is high.

As a shape example in which the contrast near the light source can be made smaller and the luminance deviation can be further reduced, in addition to the above-described shape example 31 in which the ratio R is 1.00, the shape example 29 and the ratio R in which the ratio R is 0.90 are There is a configuration example 30 of 0.86 and a configuration example 33 of the ratio R of 1.00. Therefore, suppressing the luminance deviation further by setting the ratio R of the portion having the tangential angle ψ greater than 59 ° to 0.80 or more among the portions other than the portion having the tangential angle ψ that is 39 ° or more and 59 ° or less. Is possible.

In the surface light emitting device 10, although the luminance nonuniformity can be suppressed by forming the cross-sectional shape (shape of the outer surface) of the brightness distribution forming layer 18 of the optical element 15 to a desired curved shape, It is often difficult to form the distribution forming layer 18 in a curved shape. Therefore, by forming the luminance distribution forming layer 18 by making the polygonal shape as shown below into an approximately curved shape, it becomes possible to ensure favorable workability and to suppress the luminance unevenness.

An example of the cross-sectional shape of the luminance distribution forming layer 18 of the optical element 15 is shown below (refer to FIGS. 37-39).

37 shows an example 100 of the luminance distribution forming layer 18 having a polygonal shape.

The luminance distribution forming layer 100 has an outer surface 101 parallel to the array direction of the light source and an inclination angle with respect to the array direction of the light source gradually increases as the light source approaches the light source with respect to the outer surface 101. The outer surfaces 102, 102, 103, 103, ..., 107, 107 are comprised. The luminance distribution forming layer 100 has a line symmetrical shape in the arrangement direction of the light source with respect to the center line M that crosses (crosses) the point that divides the outer surface 101 into two parts.

The luminance distribution forming layer 100 is formed by, for example, thirteen outer surfaces (line segments) having different inclination angles, but the number of outer surfaces is not limited to thirteen, and the number of outer surfaces is the distance L between light sources. It can determine arbitrarily in consideration of the like.

Since the cross-sectional shape as shown in FIG. 37 uses the luminance distribution forming layer 100 which becomes a polygonal shape approximating a curved shape, since it is not necessary to form the curved shape which may become difficult to manufacture, an optical element It is possible to secure good workability of and to suppress luminance unevenness.

Moreover, by forming the outer surface 101 parallel to the arrangement direction of the light source, it is possible to facilitate control of the minimum value φ ₀ of the front luminance φ.

38 and 39 show examples 200 and 300 of luminance distribution forming layers in which the polygonal shapes shown in FIG. 37 are divided into a plurality of structural portions.

In the luminance distribution forming layer 200 shown in FIG. 38, two structural parts 200a and 200b are alternately arranged in a plurality.

The structural part 200a has seven outer surfaces, for example, and is comprised by the outer surfaces 201, 202, 202, 203, 203, 204, and 204, and the structural part 200b also has seven outer surfaces, for example And outer surfaces 205, 206, 206, 207, 207, 208, and 208.

The outer surfaces 201 and 205 are parallel to the arrangement direction of the light source. The inclination angle with respect to the arrangement direction of the light sources on the outer surfaces 202, 203, and 204 becomes the same as the outer surfaces 103, 105, and 107 of the luminance distribution forming layer 100, respectively, and on the outer surfaces 206, 207, and 208. The inclination angle with respect to the arrangement direction of the light source is equal to the outer surfaces 102, 104, 106 of the luminance distribution forming layer 100, respectively.

Thus, by using the luminance distribution forming layer 200 which consists of the structural part 200a, 200b, 200a, 200b, ... which divided | segmented the shape of the luminance distribution forming layer 100, the number of outer surfaces of each of the structural parts 200a and 200b is obtained. Since there is little, the process of an optical element can be performed easily.

The luminance distribution forming layer 300 shown in FIG. 39 has two structural parts 300a and 300b alternately arranged in plurality.

The structural part 300a has six outer surfaces, for example, and is comprised by outer surfaces 301, 301, 302, 302, 303, and 303, and the structural part 300b also has six outer surfaces, for example, (304, 304, 305, 305, 306, 306).

The inclination angle with respect to the arrangement direction of the light sources on the outer surfaces 301, 302, and 303 becomes the same as the outer surfaces 103, 105, and 107 of the luminance distribution forming layer 100, respectively, and on the outer surfaces 304, 305, and 306. The inclination angle with respect to the arrangement direction of the light source is equal to the outer surfaces 102, 104, 106 of the luminance distribution forming layer 100, respectively.

Between the structural parts 300a and 300b, the parallel surface 307 parallel to the arrangement direction of a light source is formed. The parallel surface 307 is a surface which corresponds to the outer surface 101 of the luminance distribution forming layer 100.

Thus, by using the luminance distribution forming layer 300 which has the structure part 300a, 300b, 300a, 300b, ... which divided | segmented the shape of the luminance distribution forming layer 100, the number of outer surfaces of each of the structural part 300a, 300b is obtained. Since there is little, the process of an optical element can be performed easily.

In the case where the luminance distribution forming layer 300 is used, as shown in FIG. 40, for example, when the optical element is formed by injection molding using the mold 1000, the structural portion 300a is formed in the mold 1000. ) And a protrusion 1001 exists between the portion for forming the structural portion 300b, but the rigidity is high because the protrusion 1001 has a constant width in the arrangement direction of the light source. Therefore, deformation is unlikely to occur in the protrusion 1001, and mold release of the mold 1000 can be performed smoothly, and the processing accuracy of the formed luminance distribution forming layer 300 can be improved.

In addition, although the luminance distribution forming layer which has two structure parts arranged in multiple numbers in order was shown as an example above, the number of division of a polygonal shape is not limited to two, but may be three or more. These structures are obtained by dividing a polygonal shape into a plurality of structural parts, and there is no significant difference between the luminance distribution forming layer 100 and the optical properties which do not divide, and a structure considering workability can be arbitrarily selected.

Next, the optical element package and the optical element bonding body which are the structures which integrate the optical element 15 and the diffusing means 14 are demonstrated (refer FIG. 41 and FIG. 42).

As described above, in the surface light emitting device 10, the optical element 15, the diffusing means 14 and the optical element body 16 are arranged in this order from the light source 12, 12, ... side. Depending on the thickness, the rigidity may be low, resulting in warpage, unevenness, and the like, which may be a cause of luminance unevenness.

In order to prevent the occurrence of such warping and curling, the optical element 15 and the diffusing means 14, or the optical element 15, the diffusing means 14, and the optical element body 16 may be transparent sheets or transparent films. It is possible to configure the optical element package 21 which is packaged by the packaging member 20 such as the like (see FIG. 41).

For example, the optical element 15 and the diffusion means 14 can also be bonded together with an ultraviolet curable resin, a pressure-sensitive adhesive, or the like to form the optical element assembly 22 (see FIG. 42). . In this case, in addition to the optical element 15 and the diffusing means 14, the optical element body 16 can also be bonded to the diffusing means 14, and the optical element bonding body 22 can also be comprised.

By constituting the optical element packaging body 21 or the optical element bonding body 22, the thickness can be increased to increase the rigidity, and the occurrence of warpage and misalignment can be prevented.

In the optical element packaging body 21 and the optical element bonding body 22, the thickness d1 of the optical element 15 is 0.05 mm or more and 0.40 mm or less, and the thickness d2 of the diffusion means 14 is 1.0 mm or more and 2.5 mm or less. It is. In the case where the optical element 15 having a small thickness and small rigidity is thus used, the optical element package 21 or the optical element assembly 22 is formed by using the thick diffusion means 14. The optical element 15 can be arranged at a position approaching the light sources 12, 12,...

In addition, by forming the optical element 15 thinner with a thickness d1 of 0.05 mm or more and 0.40 mm or less, the optical element 15 is, for example, melt-extruded, and thus the substrate 17 and the luminance distribution. In the case of integrally forming by the formation layer 18, the material cost can be reduced, and the manufacturing cost can be reduced. In addition, the shape transferability can be increased, and the molding accuracy of the luminance distribution forming layer 18 can be improved.

In addition, by forming the optical element 15 thinner with a thickness d1 of 0.05 mm or more and 0.40 mm or less, the optical element 15 is formed on, for example, the substrate 17 by the ultraviolet curable resin with the luminance distribution forming layer 18. In the case of forming by bonding (joining), it is not necessary to form a thick substrate 17 such as a biaxially stretched PET film, and the thickness and the manufacturing cost can be reduced.

In addition, in the optical element 15, a part of the structural portions 18a, 18a, ... of the luminance distribution forming layer 18 may be formed in different sizes (see FIG. 43). For example, it is possible to form part of the structural portions 18a, 18a, ... so that the height in the optical axis direction is higher than the other structural portions 18a, 18a, .... By forming such an optical element 15, when the diffusion means 14 and the optical element 15 which are arrange | positioned at the brightness distribution formation layer 18 side contact, the contact area of both is adjusted. It can be made small.

Therefore, since the contact area of the diffusion means 14 and the optical element 15 becomes small, the generation | occurrence | production of the wound (damage) of the structural parts 18a, 18a, ... and the diffusion means 14 can be suppressed.

As described above, for example, as shown in FIG. 44, a part of the groove 500a for forming the mold 500 for forming the optical element 15 is formed into a deep concave shape. It is possible to form by this.

The specific shape and structure of each part shown by the best form mentioned above only showed one example of embodiment when implementing this invention, and it is interpreted that the technical scope of this invention is limited by these. It should not be.

1 is a view showing the best mode for carrying out the surface light emitting device and the liquid crystal display device of the present invention together with FIGS.

2 is a conceptual diagram showing a path of light emitted from a light source and a positional relationship between each part;

3 is a conceptual diagram showing a tangential angle in the structural portion of the luminance distribution forming layer;

4 is a graph showing a luminance distribution on an optical element of light emitted from a light source;

5 is a graph showing the luminance distribution on the diffusion means of the light emitted from the light source;

6 is a conceptual diagram showing the luminance distribution and the synthesized luminance distribution when light is emitted from a single light source;

Fig. 7 is a diagram showing a shape example of the luminance distribution together with Figs. 8 to 10, and this drawing is a conceptual diagram showing an example of a schematic triangular shape with rounded vertices;

8 is a conceptual diagram illustrating an example having an end portion in an inclined portion;

9 is a conceptual diagram illustrating an example in which a luminance level has a minimum value at a position immediately above a light source;

10 is a conceptual diagram showing an example in which the luminance level is substantially constant at a position immediately above the light source;

11 is a graph showing the relationship between the ratio L / H between the light source distance L and the optical axis direction distance H and the maximum tangential angle a;

12 is a graph showing a relationship between a moving distance x and a maximum tangential angle a;

Fig. 13 is a conceptual diagram showing each example of the cross-sectional shape of the structural part of the luminance distribution forming layer where the luminance distribution becomes substantially constant regardless of the moving distance x when viewed from any angle when L / H = 2.0;

FIG. 14 is a graph showing a relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle φ or more of the tangential angle ψ for the shape example of FIG. 13; FIG.

15 is a conceptual diagram showing respective examples of the cross-sectional shape of the structural portion of the luminance distribution forming layer in which the luminance distribution is not substantially constant when viewed from any angle when L / H = 2.0;

FIG. 16 is a graph showing a relationship between the tangential angle ψ and the tangential angle of the tangential angle φ or more of the tangential angle ψ for the shape example of FIG. 15;

17 is a chart in which the respective data are listed with respect to the shape examples shown in FIGS. 13 to 16;

18 is a conceptual diagram showing each example of a cross-sectional shape of the structural portion of the luminance distribution forming layer where the luminance distribution becomes substantially constant regardless of the moving distance x when viewed from any angle when L / H = 3.0;

FIG. 19 is a graph showing a relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle ψ or more of the tangential angle ψ for the shape example of FIG. 18; FIG.

20 is a conceptual diagram showing each example of a cross-sectional shape of the structural portion of the luminance distribution forming layer where the luminance distribution is not substantially constant when viewed from any angle when L / H = 3.0;

FIG. 21 is a graph showing a relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle φ or more of the tangential angle ψ to the shape example of FIG. 20; FIG.

FIG. 22 is a chart in which the respective data are listed with respect to the shape examples shown in FIGS. 18 to 21;

23 is a conceptual diagram showing respective examples of the cross-sectional shape of the structural part of the luminance distribution forming layer in which the luminance distribution becomes substantially constant regardless of the moving distance x when viewed from any angle when L / H = 4.0;

FIG. 24 is a graph showing a relationship between the tangential angle ψ and the tangential angle of the tangential angle φ or more of the tangential angle ψ for the shape example of FIG. 23;

25 is a conceptual diagram showing respective examples of the cross-sectional shape of the structural portion of the luminance distribution forming layer in which the luminance distribution is not substantially constant when viewed from any angle when L / H = 4.0;

FIG. 26 is a graph showing the relation between the tangential angle ψ and the tangential angle of the tangential angle φ or more of the tangential angle ψ for the shape example of FIG. 25; FIG.

27 is a chart in which the respective data are listed for the example of the shapes shown in FIGS. 23 to 26;

Fig. 28 is a graph showing the relationship between the occurrence rate (nonuniformity rate) of luminance deviation and L / H when using diffusion means having different total light transmittance T;

29 is a graph showing an enlarged view of a portion of the graph shown in FIG. 28;

30 is a graph showing the luminance distribution when the luminance distribution forming layer uses an optical element constituted by an isosceles triangle-shaped structure portion;

31 is a conceptual diagram showing each example of a cross-sectional shape of a structural portion of a luminance distribution forming layer in which L / H is 2.8 or more and less than 3.5 and the luminance distribution becomes substantially constant regardless of the moving distance when viewed from any angle;

FIG. 32 is a graph showing a relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle ψ or more of the tangential angle ψ according to the configuration example of FIG. 31; FIG.

Fig. 33 is a conceptual diagram showing each example of the cross-sectional shape of the structural part of the luminance distribution forming layer in which L / H is 2.8 or more and less than 3.5 and the luminance distribution becomes substantially constant regardless of the moving distance when viewed from any angle;

FIG. 34 is a graph showing a relationship between the tangential angle ψ and the ratio of the tangential angle of the tangential angle φ or more of the two tangential examples shown in FIG. 33; FIG.

35 is a chart showing the generation of the ratio Q and the luminance deviation in each example of the configuration;

36 is a graph showing comparisons of luminance distributions in two examples of shapes;

37 shows an example of a luminance distribution forming layer having a polygonal shape;

38 is a diagram showing an example of a luminance distribution forming layer having two polygonal structural portions;

39 is a view showing an example of another luminance distribution forming layer having two polygonal shaped structures;

40 is a view showing an optical element having two polygonal structural parts and a mold for molding the same;

41 is a conceptual diagram showing an optical element package in which an optical element, a diffusion plate, and an optical element body are packaged by a packaging member;

42 is a conceptual diagram illustrating an optical element bonding body in which an optical element and a diffusion plate are bonded to each other;

43 is a conceptual diagram showing an example in which the size of a part of the structural part of the optical element is different in size with diffusion means;

44 is a conceptual diagram illustrating an example of molding the optical element of FIG. 43;

45 is a schematic perspective view showing a conventional surface light emitting device;

46 is a conceptual view showing one example of the front luminance distribution when the distance between the light source and the diffusion plate is shortened in the conventional surface light emitting device;

47 is a conceptual diagram showing an example of the front luminance distribution in the conventional surface light emitting device;

48 is a conceptual diagram illustrating an example of front luminance distribution and gradient luminance distribution in a conventional surface light emitting device;

49 is a conceptual view showing an example in which a diffusion sheet having a high diffusing function averages the angular distribution of irradiation light beams emitted from an optical element in a conventional surface light emitting device;

Fig. 50 is a conceptual diagram showing a problem when a diffusion sheet having a high diffusion function is used in a conventional surface light emitting device.

[Description of the code]

50: liquid crystal display device, 10: surface light emitting device, 12: light source, 13a: reflective surface, 14: diffusion means, 15: optical element, 16: optical element body, 18: luminance distribution forming layer, 18a: structure part, 18b: structure part 18c: structural part, 18d: structural part, 19: air layer, 20: packaging member, 21: optical element package, 22: optical element bonding body, 100: luminance distribution forming layer, 200: luminance distribution forming layer, 200a: structural part, 200b: structural part , 300: luminance distribution forming layer, 300a: structure portion, 300b: structure portion.

Claims (25)

A plurality of light sources arranged on the same plane, An optical element having a light-transmitting property and formed with a luminance distribution forming layer for suppressing a luminance variation of light emitted from the plurality of light sources; A reflecting surface which is positioned on the opposite side of the optical element with the plurality of light sources therebetween via the air layer and reflects the light emitted from the plurality of light sources; A diffusing means positioned at opposite sides of the plurality of light sources with the optical element therebetween and diffusing the light emitted from the plurality of light sources, The distance between each center of the said light source located adjacent each other is made into the distance L between light sources, The distance in the optical axis direction from the center of the light source to the optical element is taken as the optical axis direction distance H, A distance in the direction from the light source to the light sources positioned adjacent to each other is a moving distance x, Regarding the light emitted from the light source and passing through the optical element, the front luminance on the optical element is φ, When the maximum value in the front luminance φ on the optical element is φ _max , In the range where L / H is 1.8 or more and 2.3 or less, The front luminance φ at x = L / 2 takes the minimum value φ ₀ , _{0.65 · φ max ≤ φ 0 ≤0.85} · φ max Surface-emitting device to satisfy the. A plurality of light sources arranged on the same plane, An optical element having a light transmitting property and formed with a luminance distribution forming layer for suppressing a luminance deviation of light emitted from the plurality of light sources; A reflecting surface which is positioned on the opposite side of the optical element with the plurality of light sources therebetween via the air layer and reflects the light emitted from the plurality of light sources; A diffusing means positioned at opposite sides of the plurality of light sources with the optical element therebetween and diffusing the light emitted from the plurality of light sources, A distance between each center of the light sources positioned adjacent to each other is a distance L between light sources, The distance in the optical axis direction from the center of the light source to the optical element is taken as the optical axis direction distance H, A distance in the direction from the light source to the light sources positioned adjacent to each other is a moving distance x, Regarding the light emitted from the light source and passing through the optical element, the front luminance on the optical element is φ, When the maximum value in the front luminance φ on the optical element is φ _max , In the range where L / H is 2.8 or more and 4.2 or less, The front luminance φ at x = L / 2 takes the minimum value φ ₀ , The front luminance φ at x = 0 takes the minimum value φ ₁ , _{0.65 · φ max ≤ φ 0 ≤0.85} · φ max In addition, φ ₀ <φ ₁ Surface-emitting device to satisfy. The method of claim 1, The luminance distribution forming layer of the optical element is constituted by a plurality of structural parts provided so as to project in the optical axis direction of the light emitted from the light source and to be arranged in the array direction of the plurality of light sources, In the cross-sectional shape in the stretching direction of the structural part of the luminance distribution forming layer, the angle formed by the tangent contacting the outer surface of the structural part and the surface orthogonal to the optical axis is defined as the tangential angle ψ, When the maximum tangential angle among the tangential angles ψ is the maximum tangential angle a, In the range where L / H is 1.8 or more and 2.3 or less, 35 ° + 5 ° L / H≤a≤50 ° + 5 ° L / H To satisfy The tangent angle at which the ratio of the arrangement direction components of the structural section cross-sectional shape of the outer surface portion of the structural section cross-sectional shape in the stretching direction of the structural section is 40 ° or more a or less with respect to the arrangement direction components of the structural section cross-sectional shape of the outer surface of the structural section cross-sectional shape. The ratio P of the part having ψ is 0.15≤P≤0.45 Surface-emitting device to satisfy the. The method of claim 2, The luminance distribution forming layer of the optical element is constituted by a plurality of structural parts provided so as to project in the optical axis direction of the light emitted from the light source and to be arranged in the array direction of the plurality of light sources, In the cross-sectional shape in the stretching direction of the structural part of the luminance distribution forming layer, the angle formed by the tangent contacting the outer surface of the structural part and the surface orthogonal to the optical axis is defined as the tangential angle ψ, When the maximum tangential angle among the tangential angles ψ is the maximum tangential angle a, In the range where L / H is 2.8 or more and 4.2 or less, 35 ° + 5 ° L / H≤a≤ (the smaller angle between 50 ° + 5 ° L / H and 65 °) To satisfy In the range where L / H is more than 2.8 and less than 3.5, The tangent angle at which the ratio of the arrangement direction components of the structural section cross-sectional shape of the outer surface portion of the structural section cross-sectional shape in the stretching direction of the structural section is 40 ° or more a or less with respect to the arrangement direction components of the structural section cross-sectional shape of the outer surface of the structural section cross-sectional shape. The ratio P of the part having ψ is 0.55≤P≤0.70 To satisfy In the range where L / H is 3.5 or more and 4.2 or less, The tangent angle at which the ratio of the arrangement direction components of the structural section cross-sectional shape of the outer surface portion of the structural section cross-sectional shape in the stretching direction of the structural section is 40 ° or more a or less with respect to the arrangement direction components of the structural section cross-sectional shape of the outer surface of the structural section cross-sectional shape. The ratio P of the part having ψ is 0.60≤P≤0.75 Surface-emitting device to satisfy the. The method of claim 1, The surface light-emitting device which made the total light transmittance T of the said diffusion means into 0.55 or more and 0.85 or less. The method of claim 2, The surface light-emitting device which made the total light transmittance T of the said diffusion means into 0.55 or more and 0.85 or less. The method of claim 1, The surface light-emitting device which made the total light transmittance T of the said diffusion means into 0.66 or more and 0.85 or less. The method of claim 2, The surface light-emitting device which made the total light transmittance T of the said diffusion means into 0.66 or more and 0.85 or less. The method of claim 3, Surface light emitting device formed with a polygonal shape of the outer surface of the structural portion. The method of claim 4, wherein Surface light emitting device formed with a polygonal shape of the outer surface of the structural portion. The method of claim 3, And a plane orthogonal to the optical axis between the structural portions positioned adjacent to each other. The method of claim 4, wherein And a plane orthogonal to the optical axis between the structural portions positioned adjacent to each other. The method of claim 3, And a plane orthogonal to the optical axis. The method of claim 4, wherein And a plane orthogonal to the optical axis. The method of claim 1, At least one optical element different from the optical element on the opposite side of the optical element with the diffusion means interposed therebetween, The surface light-emitting device which provided the optical element package body which wraps the said diffusing means and each optical element arrange | positioned at both sides of the said diffusing means with a packaging member. The method of claim 2, At least one optical element different from the optical element on the opposite side of the optical element with the diffusion means interposed therebetween, The surface light-emitting device which provided the optical element package body which wraps the said diffusing means and each optical element arrange | positioned at both sides of the said diffusing means with a packaging member. The method of claim 1, The surface light-emitting device which provided the optical element bonding body formed by bonding the said diffusion means and the said optical element. The method of claim 2, The surface light-emitting device which provided the optical element bonding body formed by bonding the said diffusion means and the said optical element. The method of claim 17, Let thickness d1 of the said optical element be 0.05 mm or more and 0.40 mm or less, The surface light-emitting device which made thickness d2 of the said diffusion means into 1.0 mm or more and 2.5 mm or less. The method of claim 18, Let thickness d1 of the said optical element be 0.05 mm or more and 0.40 mm or less, The surface light-emitting device which made thickness d2 of the said diffusion means into 1.0 mm or more and 2.5 mm or less. A plurality of light sources arranged on the same plane, An optical element having a light transmitting property and formed with a luminance distribution forming layer for suppressing a luminance deviation of light emitted from the plurality of light sources; A reflecting surface which is positioned on the opposite side of the optical element with the plurality of light sources therebetween via the air layer and reflects the light emitted from the plurality of light sources; Diffusing means for diffusing the light emitted from the plurality of light sources while being located on the opposite side of the plurality of light sources with the optical element therebetween; A liquid crystal panel which displays an image and is irradiated with light emitted from the plurality of light sources, A distance between each center of the light sources positioned adjacent to each other is a distance L between light sources, The distance in the optical axis direction from the center of the light source to the optical element is taken as the optical axis direction distance H, A distance in the direction from the light source to the light sources positioned adjacent to each other is a moving distance x, Regarding the light emitted from the light source and passing through the optical element, the front luminance on the optical element is φ, When the maximum value in the front luminance φ on the optical element is φ _max , In the range where L / H is 1.8 or more and 2.3 or less, The front luminance φ at x = L / 2 takes the minimum value φ ₀ , _{0.65 · φ max ≤ φ 0 ≤0.85} · φ max The liquid crystal display device to satisfy. A plurality of light sources arranged on the same plane, An optical element having a light transmitting property and formed with a luminance distribution forming layer for suppressing a luminance deviation of light emitted from the plurality of light sources; A reflecting surface which is positioned on the opposite side of the optical element with the plurality of light sources therebetween via the air layer and reflects the light emitted from the plurality of light sources; Diffusing means for diffusing the light emitted from the plurality of light sources while being located on the opposite side of the plurality of light sources with the optical element therebetween; A liquid crystal panel which displays an image and is irradiated with light emitted from the plurality of light sources, A distance between each center of the light sources positioned adjacent to each other is a distance L between light sources, The distance in the optical axis direction from the center of the light source to the optical element is taken as the optical axis direction distance H, A distance in the direction from the light source to the light sources positioned adjacent to each other is a moving distance x, Regarding the light emitted from the light source and passing through the optical element, the front luminance on the optical element is φ, When the maximum value in the front luminance φ on the optical element is φ _max , In the range where L / H is 2.8 or more and 4.2 or less, The front luminance φ at x = L / 2 takes the minimum value φ ₀ , The front luminance φ at x = 0 takes the minimum value φ ₁ , _{0.65 · φ max ≤ φ 0 ≤0.85} · φ max In addition, φ ₀ <φ ₁ Limit liquid crystal display device to satisfy. A plurality of light sources arranged on the same plane, An optical element having a light transmitting property and formed with a luminance distribution forming layer for suppressing a luminance deviation of light emitted from the plurality of light sources; A reflecting surface which is positioned on the opposite side of the optical element with the plurality of light sources therebetween via the air layer and reflects the light emitted from the plurality of light sources; A diffusing means positioned at opposite sides of the plurality of light sources with the optical element therebetween and diffusing the light emitted from the plurality of light sources, The luminance distribution forming layer of the optical element is constituted by a plurality of structural parts provided so as to project in the optical axis direction of the light emitted from the light source and to be arranged in the array direction of the plurality of light sources, A distance between each center of the light sources positioned adjacent to each other is a distance L between light sources,  The distance in the optical axis direction from the center of the light source to the optical element is taken as the optical axis direction distance H, A distance in the direction from the light source to the light sources positioned adjacent to each other is a moving distance x, In the cross-sectional shape in the stretching direction of the structural part of the luminance distribution forming layer, when the angle formed by the tangent contacting the outer surface of the structural part and the surface orthogonal to the optical axis is set as the tangential angle ψ, In the range that L / H is more than 2.8 and less than 3.5, Tangential that the ratio of the arrangement direction components of the structural section cross-sectional shape of the outer surface portion of the structural section cross-sectional shape in the stretching direction of the structural section is 39 ° or more and 59 ° or less with respect to the arrangement direction components of the structural section cross-sectional shape of the outer surface of the structural section cross-sectional shape. The ratio Q of the part with the angle ψ is 0.37≤Q≤0.70 Surface-emitting device to satisfy. The method of claim 23, wherein The ratio of the arrangement direction components of the structural section cross-sectional shape of the outer surface part of the structural section cross-sectional shape in the stretching direction of the structural part is not less than 80% in the portion other than the part having the tangential angle ψ that is 39 ° or more and 59 ° or less. A surface light emitting device which is configured to be a portion having a tangent angle ψ greater than °. A plurality of light sources arranged on the same plane, An optical element having a light transmitting property and formed with a luminance distribution forming layer for suppressing a luminance deviation of light emitted from the plurality of light sources; A reflecting surface which is positioned on the opposite side of the optical element with the plurality of light sources therebetween via the air layer and reflects the light emitted from the plurality of light sources; Diffusing means for diffusing the light emitted from the plurality of light sources while being located on the opposite side of the plurality of light sources with the optical element therebetween; A liquid crystal panel which displays an image and is irradiated with light emitted from the plurality of light sources, The luminance distribution forming layer of the optical element is constituted by a plurality of structural parts installed so as to protrude in the optical axis direction of the light emitted from the light source and to be arranged in the array direction of the plurality of light sources, A distance between each center of the light sources positioned adjacent to each other is a distance L between light sources, The distance in the optical axis direction from the center of the light source to the optical element is taken as the optical axis direction distance H, A distance in the direction from the light source to the light sources positioned adjacent to each other is a moving distance x, In the cross-sectional shape in the stretching direction of the structural part of the luminance distribution forming layer, when the angle formed by the tangent contacting the outer surface of the structural part and the surface orthogonal to the optical axis is set as the tangential angle ψ, In the range that L / H is more than 2.8 and less than 3.5, Tangential that the ratio of the arrangement direction components of the structural section cross-sectional shape of the outer surface portion of the structural section cross-sectional shape in the stretching direction of the structural section is 39 ° or more and 59 ° or less with respect to the arrangement direction components of the structural section cross-sectional shape of the outer surface of the structural section cross-sectional shape. The ratio Q of the part with the angle ψ is 0.37≤Q≤0.70 The liquid crystal display device to satisfy.

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