JPH1124583A - Plane emitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an emitter to be thin and also compact and also to obtain excellent light emission effect by sticking lens film refracting light on all the bottom face part of a grooves, or all the bottom face part, and a part or all of a peripheral wall surface and also disposing fluorescent tubes at the inside of the grooves. SOLUTION: One or more grooves 2 are provided on a rear face 1b on the opposite side to the light emission surface 1a of a light diffusing plate 1 constituted by dispersing transparent particles in transparent resin. The lens film 3 refracting the light is stuck on all the bottom face part of the groove 2, all the bottom face part and a part of the peripheral wall surface, or all the bottom face part and all the peripheral wall surface, and the fluorescent tube 4 is disposed at the inside of the groove 2. Also, a light reflecting layer 5 is desirably formed on a surface other than the light emission surface 1a of the light diffusing plate 1, namely, the rear face 1b and a side face 1c. Thus, the fluorescent tube 4 is disposed at the inside of the groove 2 of the light diffusing plate 1, so that the emitter that is formed to be thin and also compact and emits uniform light having the high luminance is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat illuminant used for a backlight or a luminous display for a liquid crystal display, a luminous sign, a luminous sign for traffic, and the like.

[0002]

2. Description of the Related Art
As a plane light emitter, place a fluorescent tube under the light diffusion plate,
In addition, a so-called direct-type flat illuminator (direct-type backlight) in which a reflecting plate or a reflecting sheet is disposed below the fluorescent tube, and an edge light in which a fluorescent tube is disposed around the periphery using a light guide plate or a light scattering light guide plate 2. Description of the Related Art A flat light-emitting body (edge light type backlight) and the like are known.

[0003] However, these flat light emitters do not sufficiently satisfy the demands of low power consumption, thinness, compactness, and the like required for so-called liquid crystal displays and the like, and there is room for improvement. In other words, the direct type has a thicker tube because the fluorescent tube is located below the light diffusion plate, and the edge light type is thinner than the direct type because the fluorescent tube is arranged around the periphery. On the other hand, it can be spread horizontally, which increases the area of the planar light-emitting body, and the problem remains in compactness.

An object of the present invention is to improve the above-mentioned circumstances, and to provide a flat light-emitting body which can be formed thin and compact and which gives a good light-emitting effect.

[0005]

According to the present invention, in order to achieve the above object, a groove is provided on a back surface or a side surface opposite to a light emitting surface of a light diffusing plate in which transparent particles are dispersed in a transparent resin. A planar light-emitting body characterized in that a lens film that refracts light is adhered to the entire bottom surface or the entire bottom surface and part or all of the peripheral wall surface, and a fluorescent tube is disposed in the groove. .

In the flat light-emitting body having such a structure, the fluorescent tube is arranged in the groove formed in the light diffusing plate, so that it is thin and compact, has high brightness, and in this case, at least the bottom surface of the groove is provided. By providing a lens film that refracts light in the part, light is dispersed due to refraction of light, and the component of light that goes straight through the film and passes through is small, so that the brightness right above the fluorescent tube is particularly bright. Uniform surface light emission is achieved without any variation or unevenness.

In this case, as the lens film, a film in which a number of transparent ridges are formed in parallel on the surface of a transparent resin film is used. Further, from the viewpoint of effective use of light (high efficiency), it is preferable to form a light-reflective layer on one or both of the back and side surfaces of the light diffusion plate, preferably on the back surface and all side surfaces.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION
This will be described in more detail with reference to an embodiment shown in the drawings. As shown in the drawing, the planar light-emitting body according to the present invention is provided with one or a plurality of grooves 2 on a back surface 1b opposite to a light-emitting surface 1a of a light diffusion plate 1 in which transparent particles are dispersed in a transparent resin. , This groove 2
, The entire bottom surface and part of the peripheral wall surface (FIGS. 2, 5), or the entire bottom surface and peripheral wall surface (FIGS. 3, 4).
6) a lens film 3 for refracting light is adhered to the fluorescent film 4, and a fluorescent tube 4 is disposed in the groove 2. Preferably, a surface other than the light emitting surface 1a of the light diffusion plate 1, that is, the back surface 1b and the side surface 1c Has a light reflective layer 5 formed thereon. Although not shown, a groove may be similarly provided on the side surface, and a fluorescent tube may be provided on the groove. However, preferably, a groove is formed on the back surface or the back surface and the side surface, and the fluorescent tube is provided on the groove. .

Here, as the transparent resin constituting the light diffusing plate, any optically transparent resin such as polystyrene resin, vinyl chloride resin, polycarbonate resin, polyethylene terephthalate resin and acrylic resin can be used without limitation. it can.

The transparent particles dispersed in the transparent resin include particles made of an inorganic material such as glass and silicon oxide, fluorine resin, polystyrene resin, acrylic resin, polycarbonate resin, silicone resin, polyethylene resin, ethylene resin. Particles made of an organic material such as a vinyl acetate copolymer can be used alone or in combination.

The shape of the transparent particles is not particularly limited, and may be spherical or crushed. In addition, as for the size, a particle having a longest diagonal length in a range of 0.1 to 50 μm in a cross section at an arbitrary position of the particle is generally used, preferably 1 to 20 μm, and more preferably 1 to 20 μm. Is 2-15
μm is good.

The amount of the transparent particles dispersed in the transparent resin is 0.005 to 5% by weight, particularly 0.01 to 1%.
It is preferred that

The planar shape of the groove formed in the light diffusing plate is basically determined by the length of the fluorescent tube used depending on the power consumption of the plane light emitter and the required luminance.
It can have a planar shape such as a W-shape or a U-shape. In addition,
The cross-sectional shape of the groove is preferably rectangular, circular, elliptical, wedge-shaped, polygonal, and the like.

The depth of the groove is preferably equal to or greater than the outer diameter of the fluorescent tube to be used. When high luminance is required, it is recommended to make the groove deeper than the diameter of the fluorescent tube. For example, in the case of a backlight, when a diffuser plate having a thickness of 4 mm and a fluorescent tube having an outer diameter of 2.6 mm are used, 2.6 to 3 mm or 2.6.
Good groove depth of ~ 3.5mm and 3mm thick diffuser plate
When using a fluorescent tube with an outer diameter of 3 mm,
A groove of ~ 4.5 mm is good. That is, in consideration of the strength of the diffusion plate, the distance t between the bottom surface of the groove and the light emitting surface is preferably set to about 0.5 to 1 mm. If the distance t is too short, the strength of the diffusion plate decreases, and if the distance t is too long, the light incident area decreases.

The groove is formed at a location where the fluorescent tube does not protrude from the periphery of the light diffusion plate and outside the light diffusion plate.
Inside the light diffusion plate.

The fluorescent tube provided in the groove is
It can be linear, L-shaped, U-shaped, W-shaped, U-shaped, etc. according to the shape of the groove. The number of fluorescent tubes is appropriately selected according to the plane size of the light diffusion plate and the required luminance, and is particularly limited. However, when the size of the light diffusing plate is represented by the length of the diagonal line of the light emitting surface (inch), about 1 to 3 for a flat light emitting body of 15 inches or less, and more than that, it is necessary. Any number can be used accordingly.

Next, as the lens film, a film in which a number of transparent ridges having a triangular, polygonal, or semicircular cross section are juxtaposed and formed on the surface of a transparent resin film can be used. A transparent resin film having a continuous pattern such as a cylindrical lens shape and a wave shape is preferable. In this case, the transparent resin film serving as the substrate is not particularly limited as long as it has transparency, such as polyester, polycarbonate, and polyethylene. In addition, the pitch of the numerous ridges is 20 to 50.
It is preferably formed to have a thickness of 0 μm, particularly 30 to 100 μm, and the height thereof is also preferably set to 20 to 500 μm, particularly 30 to 100 μm in accordance with the pitch. If it exceeds 500 μm, the film may be too thick. The continuous pattern of the ridges may be formed integrally with the transparent resin film by hot pressing or the like, or a continuous pattern of ridges formed of an appropriate transparent material separately from the transparent resin film. May be combined with a transparent resin film.

Here, it is preferable that this lens film is adhered to the inside of the groove so that the projections face the fluorescent tube.

The light-reflective layer is a light-reflective layer obtained by adding a metal-coated light-reflective film or a white pigment such as titanium white, calcium carbonate, zinc white or white luster CC to a film such as a polyethylene terephthalate or polycarbonate film. A white film or the like formed by foaming a transparent material such as a white film, polyethylene terephthalate, or polycarbonate can be used, and a light-reflective layer can be formed by sticking these at required places.

[0020]

As described above, since the fluorescent tube is disposed in the groove of the light diffusing plate, the flat luminous body of the present invention can be formed thin and compact, and can provide high brightness and uniform light. By providing a lens film capable of emitting light and refracting light in the groove, the light is dispersed by refraction of light, and the component of light that goes straight through the film and exits is small, so that the portion directly above the fluorescent tube is particularly high. Uniform surface light emission is achieved without causing unevenness, variation, or unevenness in brightness, which is bright. Therefore, it is suitably used for a backlight or a light emitting display for a liquid crystal display, a light emitting signboard, a light emitting sign for traffic, and the like.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a sectional view showing a fifth embodiment of the present invention.

FIG. 6 is a sectional view showing a sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light diffusion plate 1a Light emitting surface 1b Back surface 1c Side surface 2 Groove 3 Lens film 4 Fluorescent tube 5 Light reflective layer

Claims (4)

[Claims] 1. A groove is provided on a back surface or a side surface opposite to a light emitting surface of a light diffusion plate in which transparent particles are dispersed in a transparent resin, and the entire bottom surface of the groove or the entire bottom surface and a part of the peripheral wall surface or Attaching a lens film that refracts light to the entire surface,
A flat light-emitting body, wherein a fluorescent tube is provided in the groove. 2. The lens film according to claim 1, wherein a plurality of transparent ridges are formed in parallel on the surface of the transparent resin film.
The planar illuminator according to claim 1. 3. The flat illuminator according to claim 1, wherein the depth of the groove is equal to or deeper than the outer diameter of the fluorescent tube provided in the groove. 4. The flat light-emitting body according to claim 1, wherein a light-reflective layer is provided on one or both of the back surface and the side surface of the light diffusion plate.