JPH1124582A - Plane emitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a plane emitter to be thin and compact and also to obtain excellent light emission effect by sticking masking film having light transmissivity on all the bottom face part of grooves or all the bottom face part and a part or all of a peripheral wall face and disposing flurescent 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 masking film 3 having transmissivity is stuck on all the bottom face part of the groove 2, all the bottom face part and a part of the peripheral wall face, or all the bottom face part and all the peripheral wall face, and also the fluorescent tube 4 is disposed at the inside of the groove 2. Also, a light reflecting layer 5 is desirably formed on the 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 of the light diffusing plate 1, so that the plane emitter is formed to be thin and compact and emits uniform light having high luminance.

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 formed 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 flat luminous body, characterized in that a masking film having light transmissivity is stuck on the entire bottom surface or on the entire bottom surface and part or all of the peripheral wall surface, and a fluorescent tube is disposed in the groove. I do.

[0006] In the flat light-emitting body having such a configuration, since the fluorescent tube is arranged in the groove formed in the light diffusion plate, it is formed thin and compact, and has high brightness.
By providing a masking film having light transmittance at least on the bottom surface of the groove, the fluorescent lamp is not directly seen through, and light is partially leaked, and a certain brightness is secured, so that uniform Light emission is achieved. In this case, the total light transmittance of the masking film is preferably 80 to 1% from the viewpoint of uniformity of emission luminance.
In order to ensure high luminance, it is preferable that the depth of the groove is equal to or deeper than the outer diameter of the fluorescent tube provided in the groove. 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.

[0007]

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. The entire bottom surface of the groove 2 (FIGS. 1 and 4), the entire bottom surface and a part of the peripheral wall surface (FIGS. 2 and 5), or the entire bottom surface and the peripheral wall surface (FIGS. 3 and 3).
6) a masking film 3 having a light-transmitting property is adhered to the fluorescent film 4 and the fluorescent tube 4 is disposed in the groove 2; 1c in which a light reflective layer 5 is formed. 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 a polystyrene resin, a vinyl chloride resin, a polycarbonate resin, a polyethylene terephthalate resin, and an 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. Also, its size is
Particles having a longest diagonal length in the range of 0.1 to 50 μm in a cross section at an arbitrary position of the particle are generally used, preferably 1 to 20 μm, more preferably 2 to 15 μm.
μm is good.

The amount of the above 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 and shape of the fluorescent tube used depending on the power consumption of the planar light emitter and the required luminance.
A flat shape such as a U shape, a W shape, and a U shape can be used.
The cross-sectional shape of the groove is preferably rectangular, circular, elliptical, wedge-shaped, polygonal, or the like.

The depth of the groove is preferably equal to or greater than the outer diameter of the fluorescent tube used. When high luminance is required, it is recommended that the groove be 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 diffuser plate
When using a fluorescent tube having an outer diameter of 3 mm, a groove of 3 to 4 mm or 3 to 4.5 mm is preferable. That is, when considering the strength of the diffusion plate, the distance t between the bottom surface of the groove and the light emitting surface is 0.5 to 1 mm.
It is preferable to set the degree. 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 position where the fluorescent tube does not protrude around 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 masking film used in the present invention, a transparent resin film such as polyethylene terephthalate or polycarbonate, inorganic particles such as titanium oxide, calcium carbonate, silica, zinc oxide, silicone resin, acrylic resin, polystyrene resin Filled with resin particles having a different refractive index from the film used as the base material,
Alternatively, a transparent film coated with such a filling layer can be used. Further, a so-called lighting curtain in which a white ink having a high concealing property that hardly transmits light is arranged on a transparent resin film and the light transmittance is adjusted by adjusting the density of dots is also suitably used.

In this case, the total light transmittance of the masking film is 80 to 1%, more preferably 60 to 3%, and most preferably 50 to 5% in order to achieve the uniformity of the emission luminance of the plane light emitter. Preferably, there is.

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. The light-reflective layer can be formed by sticking these at required places.

[0019]

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 masking film that can emit light and has light transmissivity in the groove, the fluorescent tube is not directly visible, and light partially leaks, and a certain brightness is secured,
A luminous body that achieves uniform luminescence is obtained. For this reason, backlights and luminous displays for liquid crystal displays, luminous signs,
It is suitable for use as a traffic light sign.

[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]

 Reference Signs List 1 light diffusion plate 1a light emitting surface 1b back surface 1c side surface 2 groove 3 masking 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 A flat light-emitting body, characterized in that a masking film having a light transmitting property is stuck on the entire surface and a fluorescent tube is disposed in the groove. 2. A masking film having a total light transmittance of 8
The planar light-emitting body according to claim 1, wherein the plane light-emitting body has 0 to 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.