KR101030502B1 - Led back light unit and light apparatus using the same - Google Patents

Abstract

An LED backlight unit is disclosed. The disclosed LED backlight unit includes an LED package including a silicon encapsulant encapsulating the LED in a light emitting direction, a light guide plate for guiding light emitted from the LED, and an upper surface of the light guide plate to face the size of the LED package and face the LED package. A reflector integrally formed at the upper surface of the LED and reflecting the light emitted from the upper part of the LED to the lower side; Located in the to include an optical interface material for reducing the exit angle of the light emitted from the LED.

Backlight Unit (BLU), Direct Type

Description

LED backlight unit and LED lighting device using the same {LED BACK LIGHT UNIT AND LIGHT APPARATUS USING THE SAME}

The present invention relates to an LED backlight unit, and more particularly, to an LED backlight unit that allows light emitted from the LED to spread in the horizontal direction.

The backlight device of a liquid crystal display device employing a light emitting diode (LED) as a light source is classified into an edge emitting method and a direct illumination method. The side emission method sends the light from the light source to the side, and then uses a reflector or scattering pattern to redirect the light upward to provide backlighting for the liquid crystal panel.

On the contrary, in the direct method, a light source is installed below the liquid crystal panel, and the light is sent laterally from the light source, and then the light path is converted to the upper side by using a reflector to provide backlight illumination to the liquid crystal panel.

The conventional direct type LED backlight unit has a very small problem that the light emitted from the LED is mostly radiated and diffused perpendicularly to the LED chip. To solve this problem, a technique of applying a diffusion plate, applying a side emitting lens, or applying a diverter has been studied.

The technology of applying the diffusion plate is a technology introduced for the purpose of dispersing the light direction of the LED using a diffusion plate having a semi-transparent property. However, the diffusion plate has a problem that the amount of light is lowered, and even if the diffusion plate is used, the diffusion performance is reduced when the diffusion plate is closer to the LED.

Side Emitting Lenses are attached to the LED package to exit the beam in the horizontal direction. However, the effect is limited and the lens is expensive.

The diverter technology applies a transparent resin plate directly above the LED package and attaches a reflective film to a portion corresponding to the LED position of the resin plate to block vertically rising light from the LED. The diverter technology also has a disadvantage in that it is difficult to use itself and used in combination with other technologies.

1 is a schematic cross-sectional view of a conventional LED backlight unit.

Referring to FIG. 1, the LED backlight unit includes a light emitting diode (LED) 11, an LED package 10 including an encapsulant 11 encapsulating the LED, and light emitted from the LED. It includes a diffusion plate 20 to diffuse.

The encapsulant 11 is generally made of silicon and has a different refractive index than air. The refractive index of air is n: 1.0 and the refractive index of silicon is n: 1.5, and the light emitted from the LED is refracted according to the difference in refractive index between the air and the silicon encapsulant.

In general, in order for the amount of light of the LED packages arranged at regular intervals to be uniformly mixed with each other, the LED packages and the diffusion plate 20 should be spaced apart by a predetermined distance. Therefore, if the light emitted from the LED package can be diffused in the horizontal direction, the overall thickness of the LED backlight unit can be reduced.

An object of the present invention is to provide an LED backlight unit that can reduce the thickness of the LED backlight unit by allowing the light emitted from the LED to spread in the horizontal direction.

Another object of the present invention to provide an LED luminaire to which the LED backlight unit is applied.

The object of the present invention is not limited to the above-mentioned object, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

LED backlight unit according to an aspect of the present invention for achieving the above object and a light guide plate for guiding the light emitted from the LED package and the LED package including a silicon encapsulation material for encapsulating the LED in the light emitting direction, facing the LED package The reflector is integrally formed on the upper surface of the light guide plate to reflect the size of the LED package and reflects the light emitted from the upper side downward, and is formed integrally on the lower surface of the light guide plate to scatter the light reflected from the reflector in the horizontal direction. And an optical interface material disposed on an upper surface of the diffuser and the silicon encapsulation material and a lower surface of the light guide plate to reduce an emission angle of light emitted from the LED.

The light guide plate may be a plate-shaped transparent body having a refractive index of 1.3 to 1.8.

The plate-shaped transparent body covers a plurality of LED packages spaced apart from each other.

The reflector is characterized in that the mirror reflector.

The reflector is characterized in that the prism reflector.

The optical interface material has a transmittance of 50% to 90%.

The optical interface material is characterized in that the refractive index is larger than air and smaller than the silicon encapsulant.

The diffuser is printed on the lower surface of the light guide plate except the vertical upper surface of the LED package.

The diffuser is a light converging diffuser composed of a prism for the light reflected from the reflector.

LED lighting fixture according to another aspect of the invention is characterized in that it comprises the above-described LED backlight unit.

According to the present invention, the total amount of light emitted from the LED package can be increased by using the optical interface material and the diffuser.

In addition, through the LED backlight unit according to the invention it is possible to smoothly mix the light between the LEDs.

Therefore, the overall direct type LED backlight unit can be reduced in thickness.

In addition, it is possible to reduce the thickness of the LED lighting fixtures, such as LED TV using the LED backlight unit according to the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various different forms, and only the present embodiments make the disclosure of the present invention complete, and those of ordinary skill in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims.

2 is a schematic cross-sectional view of an LED package to which an optical interface material is added according to the present invention.

Referring to FIG. 2, the LED package 100 according to the present invention includes an LED 120 emitting light and a silicon encapsulant 110 encapsulating the LED 120, and an optical interface material 200. It includes.

The optical interface material 200 has a refractive index larger than that of air and smaller than the silicon encapsulant 110, and may be formed of various materials such as a film, a paste, and a solid shape. Preferably, the refractive index is in the range of 1.1 to 1.7, and a material having a low viscosity before processing and a high viscosity after processing may be advantageous in terms of LED package process. Thermoplastic transparent plastics may be used by heating, or thermosetting transparent polymers may be used after curing.

Transmittance of the optical interface material may be at least 50% and at most 100%, but preferably 85% or more and 100% or less.

The above-described optical interface material is placed on the upper surface of the silicon encapsulant and the lower surface of the light guide plate to reduce the emission angle of the light emitted from the LED. When the light emission angle is reduced, the amount of light emitted from the LED in the horizontal direction rather than the vertical direction increases.

That is, the optical interface material is applied to the silicon encapsulant 110 constituting the LED package 100 and the transparent light guide plate on the upper side of the LED package to increase the amount of light, and the light rays incident from the silicon encapsulant 110 into the air are inside. Allows exit to air without Internal Total Reflection.

It is possible to reduce the emission angle reducing effect than in the absence of the optical interface material. In the absence of the optical interface material, the light emitted from the LED is refracted in a direction in which the exit angle decreases as the refractive index decreases. However, when an optical interface material having a refractive index higher than that of air is applied, since the light emission angle does not decrease, the horizontal traveling component is increased to increase the amount of emitted light.

3 is a schematic cross-sectional view of an LED backlight unit according to an embodiment of the present invention.

Referring to FIG. 3, the LED backlight unit includes an LED package 100, an optical interface material 200, a light guide plate 300 of a transparent material, a reflector 400, and a diffuser 500.

The LED package 100 and the optical interface material 200 are as described above.

The light guide plate 300 guides the light emitted from the LED 120. The light guide plate 300 has a refractive index of 1.3 or more and 1.8 or less, and is a plate-shaped transparent body. The plate-shaped transparent body is a plate-shaped transparent body which can cover the plurality of LED packages 100 by being positioned on the upper part of the LED array that the plurality of LED packages 100 are spaced apart by a predetermined distance.

The reflector 400 faces the LED package 100 and is integrally formed on the upper surface of the light guide plate 300 to correspond to the size of the LED package 100. Preferably, by using a reflecting plate smaller than the size of the upper surface of the LED package 100, it is possible to increase the horizontal traveling component of the LED output light. A mirror may be used as the material of the reflector 400, and a prism having a light condensing function may be used.

The diffuser 500 is integrally formed on the lower surface of the light guide plate 300 to scatter light reflected from the reflector 400 to diffuse in the horizontal direction. The diffuser 500 is not disposed on all lower surfaces of the light guide plate 300, but is printed on the lower surface of the light guide plate 300 except for the vertical upper surface of the LED package 100. In the entire LED backlight unit, the diffuser 500 is positioned between the LED packages spaced apart by a predetermined distance.

Accordingly, the diffuser 500 is disposed between one end of the optical interface material on the first LED and one end of the optical interface material on the second LED among the lower surfaces of the transparent light guide plate covering both the first LED package and the second LED package. Located. As the diffuser 500, a light condensing diffuser composed of a prism for condensing the light reflected by the reflector 400 may be used.

Due to the configuration of the reflector 400 and the diffuser 500 described above, light close to the emission angle is reflected by the reflector 400, and light close to the emission angle is horizontally reflected due to the difference in refractive index. After rising and progressing in the horizontal direction, it is scattered by the diffuser 500 and is discharged to the front surface.

4 is a schematic cross-sectional view of the LED backlight unit formed by combining the unit LED package shown in FIG.

Referring to FIG. 4, a plurality of LED packages 100 are spaced apart by a predetermined distance, and the transparent light guide plate 300 having a size capable of covering the spaced apart plurality of LED packages 100 is an LED package 100. It is located at the top.

The reflective plate 400 integrally formed on the upper surface of the light guide plate 300 is attached to face the LED package so as to correspond to the size of the LED package 100. The length of the reflector is attached at the same or similar length as the length of the LED package 100. On the other hand, the diffuser 500 is bonded to the lower surface of the light guide plate between the plurality of LED packages to diffuse the light reflected from the reflector in the horizontal direction. If the reflector 400 is not present, the light emitted from the LED package 100 may be concentrated only on the upper surface corresponding to the LED package 100.

Accordingly, the light emitted from the LED package 100 in the vertical direction is reflected and diffused in the horizontal direction by using the reflector plate 400 according to the present invention.

Those skilled in the art will appreciate that the present invention can be embodied in other specific forms without changing the technical spirit or essential features of the present invention. For example, the LED backlight unit according to an embodiment of the present invention can be applied to a lighting device.

Accordingly, the embodiments described above are to be understood in all respects as illustrative and not restrictive. When the scope of the present invention is indicated by the following claims rather than the detailed description, it is intended that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention. Should be interpreted.

1 is a schematic cross-sectional view of a conventional LED backlight unit.

2 is a schematic cross-sectional view of an LED package to which an optical interface material is added according to the present invention.

3 is a schematic cross-sectional view of an LED backlight unit according to an embodiment of the present invention.

4 is a schematic cross-sectional view of the LED backlight unit formed by combining the unit LED package shown in FIG.

`` Explanation of symbols for main parts of drawings ''

100: LED package 110: LED

120: silicon encapsulation material 200: optical interface material

300: light guide plate 400: reflector

500: diffuser

Claims (10)

An LED package including a silicon encapsulation material encapsulating the LED in a light emitting direction; A light guide plate for guiding light emitted from the LED; A reflector facing the LED package and integrally formed on an upper surface of the light guide plate so as to correspond to the size of the LED package and reflecting light emitted from the upper portion of the LED downward; A diffuser formed integrally with the lower surface of the light guide plate so as to scatter light reflected from the reflector to diffuse in a horizontal direction; And And an optical interface material positioned on an upper surface of the silicon encapsulant and a lower surface of the light guide plate to reduce an emission angle of light emitted from the LED. The optical interface material, An LED backlight unit, wherein the refractive index is larger than air and smaller than the silicon encapsulant. The method of claim 1, wherein the light guide plate LED backlight unit, characterized in that the plate-shaped transparent body having a refractive index of 1.3 ~ 1.8. The method of claim 2, wherein the plate-shaped transparent body LED backlight unit to cover a plurality of the LED package spaced apart from each other. The method of claim 1, wherein the reflector LED backline unit, characterized in that the mirror reflector. The method of claim 1, wherein the reflector LED backline unit, characterized in that the prism reflector. The method of claim 1, wherein the optical interface material LED backlight unit having a transmittance of 50% to 99%. delete The method of claim 1, wherein the diffuser LED backlight unit that is printed out of the vertical top surface of the LED package of the lower surface of the light guide plate. The method of claim 1, wherein the diffuser An LED backlight unit, characterized in that the condensing combined chain consisting of a prism for condensing the light reflected by the reflector. An LED package including a silicon encapsulation material encapsulating the LED in a light emitting direction; A light guide plate for guiding light emitted from the LED; A reflector facing the LED package and integrally formed on an upper surface of the light guide plate so as to correspond to the size of the LED package and reflecting light emitted from the upper portion of the LED downward; A diffuser formed integrally with the lower surface of the light guide plate so as to scatter light reflected from the reflector to diffuse in a horizontal direction; And And an optical interface material positioned on an upper surface of the silicon encapsulant and a lower surface of the light guide plate to reduce an emission angle of light emitted from the LED. The optical interface material, An LED luminaire comprising an LED backlight unit, the refractive index of which is larger than air and smaller than the silicon encapsulant.

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