KR20080000580U - Light Emission and Diffusion Element - Google Patents

Abstract

The present invention relates to a structure of a light emitting and diffusing element, in which a fluorescent layer is formed on a transparent substrate. The fluorescent layer has a fluorescent compound, and further includes diffusion particles. The fluorescent compound may be excited by visible light or ultraviolet light so that visible light is uniformly emitted from the fluorescent layer, and thus the brightness of the structure may be enhanced.

Description

Light-Emission and Diffusion Element

The present invention relates to a structure of a light diffusion film, and more particularly, to a structure of a self-luminous diffusion film for a backlight module of a flat panel display such as a liquid crystal display (LCD).

Conventional light diffusion elements form a surface structure with roughness on the upper surface of the transparent substrate so that scattering effects occur when light passes, and thus light diffusion functions are achieved. Another conventional light diffusing element is to arrange a diffusion layer on an upper surface of a transparent substrate. The diffusion layer includes a plurality of diffusion particles and an adhesive. The diffusion particles may be buried or protrude from the adhesive to form a rough surface. The light diffusing function can be achieved when light is emitted through the diffusing layer, and the diffusing particles are naturally formed in a ball shape, and after focalizing, the light can be diffused by the lens principle.

According to the foregoing prior art, it is known that the diffusing element mainly forms a fine surface roughness or lens principle in order to provide a uniform light diffusing function. However, as the light moves through the diffusion element, it passes through the substrate, the plurality of diffusion particles, and the adhesive portion, and the light is absorbed by the material. As a result, the brightness decreases as the light utilization decreases.

In addition, a white LED used as a light source in a conventional backlight module is usually made of a blue LED having a yellow fluorescent compound using the complementary color principle, but CRI is not good because there is no red color.

An object of the present invention is to mix a fluorescent compound with a diffusion layer and to use light having a specific wavelength for stimulating the fluorescent compound, so that light having another specific wavelength can be emitted from the fluorescent compound itself, and thus the visible angle and uniformity of the light. This allows sex to be broader, more consistent, and to increase brightness.

Another object of the present invention is to convert the chromaticity of light after it has been transmitted by control for fluorescence compound color mixing; This may alleviate the disadvantages of inferior CRI of white LEDs manufactured by the blue / yellow light complementary principle in conventional backlight modules.

According to an aspect of the present invention, a light emitting and diffusing element includes a transparent substrate having a first surface and a second surface opposite to the first surface; And a fluorescent layer formed on the transparent substrate, wherein the fluorescent layer has a fluorescent compound, and the fluorescent compound is excited by light having a first wavelength so that at least one light having a second wavelength may be emitted. .

According to another aspect of the present invention, a light emitting and diffusing element, a transparent substrate having a first surface and a second surface facing the first surface; A fluorescent-emitting layer formed on the first surface of the substrate, the fluorescent-emitting layer having a fluorescent compound, wherein the fluorescent compound is excited by light having a first wavelength such that at least one light having a second wavelength is A fluorescence-emitting layer that can be emitted; And a diffusion layer formed on the surface of the fluorescent-emitting layer opposite the surface of the first surface of the transparent substrate, wherein the diffusion layer includes a diffusion layer including diffusion particles.

Preferred embodiments are illustrated together with the drawings to clearly understand the objects, functional features and advantages of the present invention as described above.

Fig. 1 schematically shows the structure of a light emitting and diffusing element of a first embodiment of the present invention, wherein the light emitting and diffusing element comprises a substrate 11 which transmits light, each of which has a top surface 11a. ) And bottom surface 11b. On the upper surface 11a of the substrate 11, a UV-curable transparent fluorescent layer 12 may be formed using a coating method. The fluorescent layer 12 includes a fluorescent adhesive portion 12b and diffusion particles 12a. The fluorescent adhesion part 12b contains a fluorescent compound and an adhesive agent. The diffusion particles 12a may be fixed to the upper surface 11a of the substrate 11 by the fluorescent adhesive part 12b. An antistatic layer 14 is disposed on the bottom face 11b.

When light having a specific wavelength, such as visible light in the wavelength range of 400 nm to 760 nm or ultraviolet light in the wavelength range of 200 nm to 380 nm, is incident on the light emitting and diffusing element, a part of the light is diffused to the particles 12a and the fluorescence. After passing through the adhesive portion 12b and a part of the light is fused with the fluorescent compound, visible light having at least one wavelength, for example, light having a wavelength in the range of 400 nm to 760 nm is excited, thereby diffusing and emitting the light emitting sheet ( The sheet not only diffuses the light but can also emit other light itself, so that its brightness is enhanced and the diffusion angle is uniformly constant.

Table 1 shows a specification table for an example of a light emitting and diffusing device according to the present invention. The last two items in Table 1 illustrate a comparison of the brightness and uniformity of light between a photometric backlight module using a conventional prism sheet and a diffusion sheet and a photometric backlight module using a fluorescent diffusion layer. According to the comparison, the light uniformity of the backlight module of the fluorescent diffusion sheet of the present invention is 96%, which is higher than the conventional 89%, and the central brightness is 3625, which is lower than the conventional 3750 candle power / cm 2, which means that the light emitted from the whole It is distributed more uniformly than before, meaning that the object for improvement has been achieved.

Table 1 : Note: V = Vertical, H = Horizontal

Inspection items unit Check value method of inspection Full thickness Μm 160 ± 10% Board thickness Μm 100 Chromaticity change Chroma X 0.264 ± 0.04 Chroma Y 0.284 ± 0.04 CRI 85 to 95 Flame-proof To OK UL94 VTM-2 Heat shrink MD (V) % 0.9 ASTM D1204 150 ℃ TD (H) % 0.1 ASTM D1204 150 ℃ The tensile strength MD (V) Kg / mm ² 23.2 ASTM D882 TD (H) Kg / mm ² 25.5 ASTM D882 Tensile strength at rupture MD (V) % 191 ASTM D882 (JIS 2151) TD (H) % 174 ASTM D882 (JIS 2151) Surface resistance Ω ≥10 ¹² JIS K 6911 15-inch metering module (white light CCFL + prism sheet (2) + upper diffuser sheet + lower diffuser sheet) Center brightness 3750 9pt.uniformity 89% 15-inch metering module (UV-CCFL + fluorescent diffuser sheet) Center brightness 3625 9pt.uniformity 96%

Figure 2 schematically shows the structure of the light emitting and diffusing element of the second embodiment of the present invention. The main difference from the first embodiment is that the fluorescent light emitting layer 22 and the diffusing layer 23 have an independent structure, the fluorescent light emitting layer 22 includes a fluorescent compound and an adhesive, and the diffusion layer 23 includes a diffusing particle and an adhesive. The thickness of the fluorescent light emitting layer 22 is about 40 to 50 µm and the thickness of the diffusion layer 23 is about 15 to 20 µm. When the incident light is ultraviolet light, it is completely absorbed by the fluorescent light emitting layer 22, and visible light having at least one wavelength such as visible light having a wavelength in the range of 400 nm to 760 nm is excited.

The light emitting and diffusing film may be generated by the method described below.

1. A coating method forms an antistatic layer on one surface of the substrate and bakes the layer until cured.

2. Zinc oxide (or rare earth oxide of yttrium oxide or lanthanum oxide) A fluorescent coating gel is prepared by uniformly mixing a fluorescent powder with a polymer and a solvent. The polymer may be UV cured after adding a light inducing material. Polymers are made of polystyrene (PS), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), epoxy resin or polyethylene terephthalate (PET). It may be an optical plastic material.

3. Select diffusion particles having a size in the range of 15 μm to 80 μm and blend with the fluorescent coating gel. The diffusion particles may be a material of PS, PMMA, PC, PE, PP, PVC, epoxy resin, poly (lactic acid) (PLA), PET, SiO 2, or Al203.

4. The fluorescent coating gel mixed with the diffusing particles may be coated on the other surface of the substrate by a coating method, specifically, by a roll-to-roll method, polymerization may occur by exposure to an ultraviolet light lamp. Thus, the gel can be cured on the substrate.

5. The fluorescent diffusion layer can be cured not only by ultraviolet light but also by baking method, and the operating temperature is about 70 ° C to 120 ° C.

The present invention relates to a structure of a light emitting and diffusing element, wherein the structure has a fluorescent layer having a fluorescent compound and a diffusing layer having diffusing particles formed on a transparent substrate, and the fluorescent compound is excited by visible or ultraviolet light. Since the visible light is emitted from the fluorescent layer, the brightness is enhanced than that of the conventional backlight module, and a backlight module having a wider and more consistent viewing angle and uniformity of light can be obtained, which can be widely used for manufacturing LEDs.

1 is a schematic diagram showing the structure of a first embodiment of the present invention.

2 is a schematic view showing the structure of a second embodiment of the present invention.

Claims (6)

In the light emitting and diffusing element for a backlight module of a liquid crystal display (LCD), A transparent substrate having a first surface and a second surface opposite to the first surface; And A fluorescent layer formed on the first surface of the transparent substrate Wherein the fluorescent layer has a fluorescent compound, and the fluorescent compound is excited by light having a first wavelength, so that at least one light having a second wavelength can be emitted. The method of claim 1, The fluorescent layer comprises a light emitting and diffusion device comprising a diffusion particle. The method of claim 1, Wherein the light having the first wavelength is visible light having a wavelength in the range of 400 nm to 760 nm or ultraviolet light having a wavelength in the range of 200 nm to 380 nm. The method of claim 1, The light having the second wavelength is light emitting and diffusing element, characterized in that the visible light having a wavelength in the range of 400nm to 760nm. The method of claim 2, The diffusion particles are light emitting and diffusion device, characterized in that the size of 15㎛ to 80㎛. The method of claim 2, And the diffusion particles are selected from the materials of PS, PMMA, PC, PE, PP, PVC, epoxy resin, polylactic acid (PLA), PET, SiO2 and Al203.