KR20110048397A - LED Package and Backlight Assembly using the same - Google Patents

Abstract

PURPOSE: An LED package and a backlight assembly using the same are provided to increase the efficiency of a process of implanting fluorescent material into a chip by implementing white light through a color conversion layer including an additional fluorescent material. CONSTITUTION: In an LED package and a backlight assembly using the same, at least one LED chip(130) is accommodated into a package body(120). The package body has uniform inclination around the LED chip and has a reflection function. A color conversion layer(150) converts radiated light into a white light. The color conversion layer includes a yellow fluorescent materials or a compound of red and green fluorescent materials A lens unit(140) is formed on the top of the LED chip and controls the orientation angle of light.

Description

Light emitting diode package and backlight unit using the same {LED Package and Backlight Assembly using the same}

The present invention relates to a light emitting diode package for use in a backlight unit for lighting or display.

LED, which converts an electrical signal into light using characteristics of a compound semiconductor, has a long life, low driving voltage, and low power consumption compared to other light emitters. In addition, it has the advantages of excellent response speed and impact resistance as well as small size and light weight.

With the trend toward miniaturization and thinning of information and communication devices, LEDs are becoming smaller and smaller, such as resistors, capacitors, and noise filters. Recently, surface-mounted devices are directly mounted on a printed circuit board (PCB). It is made of (Surface Mount Device) type. Accordingly, LED lamps are also being developed as surface mount devices. Such surface-mounted LED lamps can replace the existing simple lighting lamps, which are used for lighting indicators of various colors, character displays, and image displays, and are not only used as light sources of portable electronic devices such as mobile phones. Recently, it is used as a backlight unit (BLU) of a liquid crystal display (LCD), a light source for illumination, and the like. In addition, it is possible to implement a variety of colors, the application range is increasing considerably due to the advantages such as high color rendering, stability, energy saving.

Referring to FIG. 1, this is a view illustrating a configuration example in which a conventional white LED package forms a backlight assembly. The conventional white LED package 10 includes an LED blue chip 11 and a yellow. The fluorescent material 13 is formed between the left and right spaces of the reflective frame 17 having the same inclined surface, a plurality of the white LED package 10 is a printed circuit board (Printed Circuit Board, PCB) at equal intervals (15) It is mounted on). The white LED package 10 emits blue light from the LED blue chip 11 and absorbs a portion of the blue light by a yellow fluorescent material 13 to produce yellow light, and the yellow fluorescent light. The remaining blue light and the yellow light which are not absorbed by the material 13 are mixed to emit white light. The plurality of white LED packages 10 are mounted on the printed circuit board (PCB) 15 at equal intervals and used as a light source of a backlight assembly.

Such a conventional LED package inevitably undergoes a process of injecting a fluorescent material onto the LED blue chip 11 to produce a white light LED. In such a manufacturing process, a tray containing a phosphor in an LED package is required, and a white light LED can be realized only by accurately matching RGB values with the phosphor. However, when the error occurs, the injection and mixing of the phosphors cause variations in the light color coordinates of each LED, which leads to a defect, which causes a problem of greatly reducing the reliability of the product.

The present invention has been made to solve the above-described problem, an object of the present invention is not a structure for inserting a phosphor on the LED chip to constitute a light emitting diode package, but includes a fluorescent material independent of the general LED chip The present invention provides a light emitting diode package capable of increasing productivity by removing a process of injecting a fluorescent material finely on a chip by implementing a white light by providing a separate color conversion layer.

The present invention to solve the above problems, at least one LED chip accommodated in the package body; A color conversion layer spaced apart from the LED chip to convert the emitted light into white light; It is possible to provide a light emitting diode package comprising a.

In particular, the LED chip in the present invention is a blue LED, the color conversion layer may be formed including a yellow phosphor or a mixture of red and green phosphor. In this case, the color conversion layer is formed of a sheet or glass structure formed of any one material selected from YAG (yttrium-aluminum-based), TAG (terbium-aluminum-based), and silicate.

Alternatively, in the configuration of the LED package according to the present invention, the LED chip may be formed as an ultraviolet LED chip, in which case the color conversion layer is formed of a sheet or glass structure formed with a mixture of blue, green and red phosphors. Can be.

In any case, the light emitting diode package according to the present invention may have a structure in which a lens unit for adjusting the directing angle of light is further formed on the upper surface of the LED chip, in which case the lens unit has a concave, convex or hemispherical shape. The material may be formed of an epoxy resin, a silicone resin, a urethane resin, or a mixture thereof.

The light emitting diode package according to the present invention described above may be used as a general light source for lighting or backlight, and in particular, when applied to a backlight assembly, may be formed as follows.

A light guide plate including a light emitting diode package having the above-described structure, the light guide plate being configured at one side of the light emitting diode package to guide light upward; A reflection plate positioned under the light guide plate to reflect light leaked from the light guide plate to an upper portion thereof; The backlight assembly may be disposed on an upper portion of the light guide plate, and may include an optical sheet for uniforming the luminance of light emitted from the light guide plate. In this case, the color conversion layer of the light emitting diode package may be disposed under the optical sheet.

According to the present invention, a white light is implemented by providing a separate color conversion layer including a fluorescent material independent of a general LED chip, not a structure in which a phosphor is inserted on an LED chip to construct a light emitting diode package. By removing the process of injecting a fluorescent material fine on the phase it is possible to increase the efficiency of the process to increase the productivity.

In particular, in the case of an array in which a plurality of LED chips are formed, it is possible to reduce the difference between individual LEDs that cause distortion in color coordinates, so that it can be utilized as a light source with high reliability, and white light can be realized through a color conversion layer without additional processing. It also has the effect of reducing manufacturing costs.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation according to the present invention. In the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and duplicate description thereof will be omitted. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

In the present invention, in forming a light emitting diode package that implements white light, not a structure in which a fluorescent material is injected onto an individual LED chip, but a package having a structure for forming an independent color conversion sheet on the LED chip, a manufacturing process And improving the reliability of the product.

Referring to FIG. 2A, this illustrates an embodiment of a light emitting diode package according to the present invention.

As shown in (a) shows the structure of the basic LED package according to the present invention, the LED package according to the present invention is spaced apart from the LED chip and at least one LED chip 130 accommodated in the package body 120 And a color conversion layer 150 arranged to convert the emitted light into white light.

The package body 120 may be formed in an inclined structure to perform a reflection function having the same inclination around the LED chip 130. In particular, the LED chip is connected to the lead frame 111 having the circuit pattern of the printed circuit board by a wire 131 so as to be electrically connected to the printed circuit board 110 formed under the package body, or without a separate wire bonding. It can also be implemented in a structure that is connected in a flip chip type.

In the LED chip 130 according to the preferred embodiment of the present invention, the LED chip is specifically, the LED chip 130 has a light emission wavelength in the visible or near infrared region, high luminous efficiency, and the pn junction It can be made of materials that satisfy the conditions, such as being possible to manufacture. Such materials include gallium nitride (GaN), gallium arsenide (GaAs), gallium phosphide (GaP), gallium-arsenide-phosphorus (GaAs1-xPx), gallium-aluminum-arsenic (Ga1-xAlxAs), and indium phosphide (InP) Compound semiconductors such as indium-gallium-phosphorus (In1-xGaxP) may be used. Particularly preferably, a group III nitride-based blue LED such as GaN is preferably used. In this case, the color conversion layer 150 may be formed of YAG (yttrium-aluminum-garnet-based) or TAG (terbium-aluminum-garnet-based) or silicate. It is preferably configured to include a yellow phosphor layer formed of any one material selected from the system. Particularly preferably, it may be implemented as a sheet or a transparent substrate coated with a material of YAG (yttrium-aluminum-based garnet).

According to this configuration, the blue light emitted from the blue LED is absorbed by the phosphor as it passes through the color conversion layer including the yellow phosphor, and the yellow phosphor is excited, and visible by the secondary light generated by this energy conversion. The light of the entire light ray area is generated so that colors are mixed by scattering of the generated lights, and white light can be realized by such color mixing. In addition, reference numeral 160 of FIG. 2A illustrates an optical sheet that may be formed when the LED package according to the present invention is applied to the backlight unit.

In the above-described embodiment, an example of implementing white light as a color conversion layer including a blue LED and a yellow phosphor has been described, but this is a preferred embodiment and the idea of implementing white light due to the combination of the LED and the color conversion layer used is It will be apparent to be included in the gist of the present invention.

For example, a phosphor is a material that absorbs and emits light emitted from an LED chip or emits light by absorbing light emitted from another phosphor. LED chips can emit blue, green or red depending on the type of impurities. Therefore, the white light can be emitted by the combination of the LED chip and the phosphor. For example, the blue LED chip may combine with yellow phosphors or with red / green phosphors to emit white light. As another example, the ultraviolet LED chip may emit white light by combining with a red / green / blue phosphor. Therefore, the light emitting diode package according to the present invention can be implemented by implementing a color conversion layer corresponding to the LED chip used by using the above-described mixed phosphor material.

As a more specific application example, white light can be realized by mixing three primary colors of red, green, and blue, or mixing two colors in complementary colors. White light by three primary colors can be realized by using a first phosphor that absorbs primary light emitted by the LED chip and emits red, a second phosphor that emits green, and a third phosphor that emits blue. Therefore, when the color conversion layer according to the present invention is implemented as a separate color conversion layer including the first to third phosphors described above, the white light emitting diode package according to the present invention may be implemented.

In addition, white light can be realized by mixing primary light and secondary light by using an LED chip that emits blue light, a first phosphor that absorbs the blue light to emit red light, and a second phosphor that emits green light.

In addition, by implementing the first and second phosphors independently as a color conversion layer, it is possible to implement a light emitting diode package to implement white light.

In addition to the above-described examples, the white light emission using the complementary color may use, for example, a first phosphor that absorbs primary light from an LED chip and emits blue light, and a second phosphor that absorbs blue light and emits yellow light, or from an LED chip. This can be achieved by using a first phosphor that absorbs light emission of light and emits green light and a second phosphor that absorbs green light and emits red light. In addition, by implementing the first and second phosphors independently as a color conversion layer, it is possible to implement a light emitting diode package to implement white light.

In the above-described embodiment, the blue phosphors include ZnS: Ag, ZnS: Ag + In ₂ O ₃ , ZnS: Zn + In ₂ O ₃ , (Ba, Eu) MgAl ₁₀ O ₁₇ , and the green phosphor is ZnS: Cu , Y ₂ Al ₅ O ₁₂ : Tb, Y ₂ O ₂ S: Tb and the like, and the red phosphor is Y ₂ O ₂ S: Eu, Y ₂ O ₃ : Eu, YVO ₄ : Eu and the like. In addition, YAG: Ge, YAG: Ce and the like may be used as the yellow phosphor.

The light emitting diode package according to the present invention may include a protective material layer 132 that is further filled with silicon-based resin on the LED chip, and the heat dissipation structure for emitting heat sources of the LED to the outside of the printed circuit board. It is preferable to further comprise (H).

In addition, the present invention may further comprise a lens unit 140 formed on the top of the LED package, as shown in the structure shown. The lens unit 140 includes a lens to increase the directing angle of the light emitted from the LED. For this purpose, a lens having a concave, convex, or hemispherical shape is mounted to improve uniformity of the linear light source in the LED module. You can do it. In addition, the lens may be formed of an epoxy resin, a silicone resin, a urethane resin, or a mixture thereof. In particular, the lens is preferably smaller than the refractive index of the above-described protective material layer 132, through which the total reflection caused by the difference in refractive index can be suppressed to increase the light extraction efficiency.

The light emitting diode package according to the present invention may be applied to various products such as an illumination light source or a backlight unit of a liquid crystal display device, and in particular, when applied to the backlight unit, it may be implemented in the following configuration.

That is, the light emitting diode package according to the present invention includes a light guide plate configured to guide light upward, and is disposed on one side of the light guide plate, and is located at the bottom of the light guide plate to reflect the light leaked from the light guide plate to the upper part of the light guide plate. The optical sheet may be positioned to include an optical sheet for uniforming the luminance of light emitted from the light guide plate. That is, the optical sheet 160 disposed in FIG. 2A illustrates a configuration example when the optical sheet 160 is implemented as a backlight unit. 2B illustrates a structure for implementing white light through an array of a plurality of light emitting diode packages according to the present invention. That is, a process of converting blue light derived from the blue LED described in this embodiment into white light while passing through the color conversion layer 150 according to the present invention. Conventionally, the inconvenience of injecting a fluorescent material into each LED chip, and the problem that the deviation occurs due to the light color coordinates due to the error of the injection process in the present invention to implement the color conversion layer 150 to solve the temporary It becomes possible.

In the foregoing detailed description of the present invention, specific examples have been described. However, various modifications are possible within the scope of the present invention. The technical idea of the present invention should not be limited to the embodiments of the present invention but should be determined by the equivalents of the claims and the claims.

1 is a schematic diagram illustrating a structure of an LED package applied to a backlight unit according to the prior art.

2A and 2B are schematic structural diagrams showing a structure and an application example of the LED package according to the present invention.

Claims (9)

At least one LED chip housed in the package body; A color conversion layer disposed spaced apart from the LED chip and converting the emitted light into white light; Light emitting diode package comprising a. The method according to claim 1, The LED chip is a blue LED, The color conversion layer is a light emitting diode package, characterized in that formed including a yellow phosphor or a mixture of red and green phosphor. The method according to claim 2, The color conversion layer is formed of at least one sheet or glass structure formed of any one material selected from YAG (yttrium-aluminum-based garnet), TAG (terbium-aluminum-based garnet), and silicate. LED package. The method according to claim 1, The LED chip is an ultraviolet LED chip, The color conversion layer is a light emitting diode package, characterized in that formed of at least one sheet or glass structure formed with one or more substances or a mixture of two or more of blue, green, red phosphor. The method according to any one of claims 1 to 4, The upper surface of the LED chip, the light emitting diode package, characterized in that the lens portion for adjusting the directivity of the light is further formed. The method according to claim 5, The lens unit, A light emitting diode package comprising a lens having a concave, convex or hemispherical shape. The method according to claim 6, The lens is a light emitting diode package, characterized in that made of an epoxy resin, a silicone resin, a urethane resin or a mixture thereof. A light emitting diode package according to any one of claims 1 to 3; A light guide plate configured on one side of the light emitting diode package to guide light upward; A reflection plate positioned under the light guide plate to reflect light leaked from the light guide plate to an upper portion thereof; And an optical sheet positioned on the light guide plate, the optical sheet uniforming the luminance of light emitted from the light guide plate. The method according to claim 8, The color conversion layer of the light emitting diode package is a backlight assembly unit, characterized in that disposed under the optical sheet.

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