KR101505430B1

KR101505430B1 - LED package

Info

Publication number: KR101505430B1
Application number: KR1020080062390A
Authority: KR
Inventors: 정정화; 김도형
Original assignee: 서울반도체 주식회사
Priority date: 2008-06-30
Filing date: 2008-06-30
Publication date: 2015-03-31
Also published as: KR20100002484A

Abstract

Here, an LED package using different kinds of phosphors having different excitation wavelengths is disclosed. The LED package includes a package body having a cavity, an LED chip mounted on a bottom surface of the cavity, a first phosphor positioned adjacent to a sidewall of the cavity, an excitation wavelength different from that of the first phosphor, And a second phosphor regionally isolated from the first phosphor.

Phosphor, LED, chip, isolation, encapsulant, molding part

Description

LED package {LED PACKAGE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED package, and more particularly, to an LED package using a different kind of phosphor having different excitation wavelengths.

Various electronic devices such as a mobile communication terminal, a digital camera, a notebook computer, a monitor, and a TV are provided with a display device for displaying an image. Various types of display devices can be used, but a display device having a flat plate shape is mainly used due to the characteristics of electronic devices, and in particular, an LCD for displaying an image using a liquid crystal is widely used. LCDs have advantages of being thinner and lighter than other display devices, lower driving voltage and lower power consumption.

LCD is a non-luminescent device that does not emit light by itself because an LCD panel displaying an image substantially requires a back light unit for supplying light to the LCD panel. BACKGROUND ART In recent years, a backlight unit using a cold cathode fluorescent lamp (CCFL) as a light source has been widely used. Recently, an LED having an environmentally friendly, fast response speed, low voltage characteristics, and a compact structure has been used as a light source The use of backlight units is increasing.

Conventionally, an LED package including a blue LED chip and a yellow phosphor is known as a light source of a backlight unit. In such an LED package, a part of blue light emitted from the LED chip is converted into yellow light, and white light is realized by mixing blue light and yellow light. However, when applied to a backlight unit, conventional LEDs and packages have limitations in that the color reproduction rate is lowered even when the R, G, and B color filters are applied. For example, when the R, G, and B color filters are applied and the YAG yellow phosphor is used, the color reproduction ratio is only about 73% of the NTSC and when the general yellow phosphor is used, the color reproduction ratio is about 68 % (Compared to NTSC). When a yellow phosphor is used, a pattern of a spectrum in which blue and green and red wavelengths of white light are mixed with light of green and red wavelengths, that is, peaks of wavelengths corresponding to green and red are substantially absent It is because of bet.

Further, an LED package that produces white light by a combination of red and green phosphors and blue LED chips having different excitation wavelengths is also conventionally known. Such an LED package has blue, green, and red peak wavelengths, so that it has better color rendering and color reproducibility than an LED package using a single phosphor. However, such a conventional LED package has a problem that the light loss is large and the efficiency of the phosphor is also inferior because different kinds of phosphors are placed in one encapsulant without being isolated from each other.

If a different kind of fluorescent material having different excitation wavelengths is used, white light of a color temperature which can not be realized by combination of a conventional LED chip and phosphors can be obtained. For example, in an LED package that produces white light by a combination of a blue LED chip and a yellow phosphor, white light of 3000 K color temperature can be obtained, for example, by correcting white light with an excitation wavelength of a red phosphor. However, even when different kinds of phosphors are used for such an application, the problems of light loss and efficiency reduction are also present because different phosphors can not be isolated from each other in one region.

Accordingly, it is an object of the present invention to provide a phosphor that can improve the color rendering and color reproducibility of light by using different types of phosphors having different excitation wavelengths, and that the different types of phosphors are regionally isolated from the optimum positions LED package.

According to one aspect of the present invention, there is provided a light emitting device comprising: a package body having a cavity; an LED chip mounted on a bottom surface of the cavity; a first phosphor positioned adjacent to a sidewall of the cavity; And a second phosphor regionally isolated from the first phosphor is provided.

Preferably, an encapsulant is formed in the cavity, the encapsulant being at least partially transparent. The encapsulant includes an annular first molding part formed to face the side wall face of the cavity, and at least a part of the annular first molding part formed inside the first molding part And a second molding part covering the LED chip.

According to one embodiment of the present invention, the first phosphor is contained in the first molding part, and the second phosphor is contained in the second molding part.

According to an embodiment of the present invention, the first phosphor is contained in the first molding part, and the second phosphor is contained in the resin molding part covering the LED chip in the second molding part.

According to an embodiment of the present invention, the sealing material further includes a first molding part formed in the cavity and a third molding part formed on the upper side of the second molding part, wherein the first phosphor is contained in the first molding part And the second phosphor is included in the third molding part.

According to an embodiment of the present invention, the light emitting device further includes a translucent film attached to the top of the encapsulant, wherein the first phosphor is contained in the first molding part, and the second phosphor is contained in the translucent film.

According to an embodiment of the present invention, the LED chip may be a blue LED chip, the first phosphor may be a red phosphor, and the second phosphor may be a yellow phosphor.

According to an embodiment of the present invention, the LED chip may be a blue LED chip, the first phosphor may be a red phosphor, and the second phosphor may be a green phosphor.

According to an embodiment of the present invention, the sidewall surface of the cavity may be a reflective surface inclined at a portion facing the annular molding portion.

According to an embodiment of the present invention, the first molding part may be formed of a reflective resin material, and may have a tilted reflecting surface on an inner circumferential surface thereof.

According to the present invention, it is possible to enhance the color rendering and color reproducibility of light by using different types of phosphors having different excitation wavelengths, while locally isolating the different kinds of phosphors at optimal positions capable of reducing light loss, It is possible to minimize the loss and increase the efficiency. According to one embodiment, a kind of phosphor may be included in a molding portion formed in an annular shape on a cavity side wall surface of the package body, for example, in order to isolate the different kind of phosphors. In this case, the molding portion is formed in advance in the annular shape on the cavity side wall surface, Next, another molding part is formed to complete the sealing material, so that the air layer in the complicated shape part in the cavity can be reduced or eliminated, which contributes to prevention of lowering of the reliability of the LED package due to the generation of bubbles in the sealing material.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, and the like of the components may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

1 is a cross-sectional view illustrating an LED package according to a first embodiment of the present invention.

1, the LED package 1 according to the present embodiment includes a package body 10, an LED chip 2, a sealing material 20, and first and second phosphors 32 and 34 . A concave cavity defined by the bottom surface 12 and the side wall surface 14 is formed on the package body 10.

The LED chip 2 is mounted on the bottom surface 12 of the cavity. Although the illustration is omitted, lead terminals for inputting power to the LED chip 2 are positioned on the bottom surface 12 of the cavity. The package body 10 may be formed using a resin such as PA or PPA, and may be formed of silver, color, silver white, or the like capable of reflecting light.

In the cavity, a translucent encapsulant 20 including a first molding part 22 and a second molding part 24 is formed. The first and second molding portions 24 are sequentially formed using a light-transmitting epoxy and / or a silicone resin as a main component. The first and second molding parts 22 and 24 can serve as a sealing material and a fence for isolating the first phosphor 32 and the second phosphor 34 from each other.

According to the present invention, the first phosphor (32) and the second phosphor (34) are different kinds of phosphors having different excitation wavelengths. The first phosphor 32 is contained in the first molding part 22 in the form of particles and the second phosphor 34 is contained in the second molding part 24 in the form of particles.

The first molding part 22 including the first phosphor 32 is formed in a substantially annular shape facing an inclined sidewall of the cavity. Therefore, the peripheral region of the LED chip 2 is located inside the first molding part 22. [ The second molding part 24 including the second fluorescent material 34 is formed to fill the remaining space of the cavity except for the part occupied by the first molding part 22. Accordingly, the second molding part 24 is bounded by the first molding part 22 in the inner part of the first molding part 22.

1 in which the first molding portion 22 is located outside the second molding portion 24 at the same height and the arrangement in which the first phosphor 32 and the second phosphor 34 are disposed in the region By virtue of the isolated structure, the mutual interference between the two kinds of phosphors can be reduced, and the phosphor concentration in the encapsulant can also be reduced. This is possible because the arrangement and structure can convert the light passing through the reflection surface in the cavity and the non-light into the wavelengths by the first and second phosphors 32 and 34 sharing the light.

According to an embodiment of the present invention, it is possible to apply white light by combining a blue LED chip, a red phosphor, and a green phosphor. In this case, it is preferable that the first phosphor 32 in the first molding part 22 is a red phosphor and the second phosphor 34 in the second molding part 24 is a green phosphor.

Since the second phosphor 34 is relatively in the vicinity of the light emitting surface of the sealing material and is a green phosphor having a higher energy level than that of the red phosphor, the red phosphor, that is, the first phosphor 32, The light of the converted wavelength can be emitted to the outside in the form of reflection or transmission without wavelength conversion.

According to an alternative embodiment of the present invention, it is possible to apply white light by a combination of a blue LED chip, a red phosphor, and a green phosphor. In this case, it is preferable that the first fluorescent material 32 in the first molding part 22 is a red fluorescent material and the second fluorescent material 34 in the second molding part 24 is a yellow fluorescent material.

At this time, the white light is obtained by only a combination of the yellow phosphor, the blue LED and the chip, and the red phosphor can serve to correct such light to a solar light, more preferably warm white light. The combination of the above-mentioned blue LED chip, yellow phosphor and green phosphor allows the LED package 1 to realize light in the vicinity of the blackbody radiation curve shown in the chromaticity graph of FIG.

Fig. 2 shows a manufacturing process of the LED package shown in Fig.

2 (a), a core 50, which covers a part of the space where the second molding part 24 is to be formed and defines a space in which the first molding part 22 is to be molded, (10a). &Lt; / RTI >

Next, referring to FIG. 2B, silicon or epoxy resin including the first phosphor 32 is filled between the core 50 and the sidewall surfaces of the cavity 10a to form the annular first molding part 22 Is formed to face the inclined side wall surface of the cavity.

Next, referring to FIG. 2C, the core 50 is removed from the cavity 10a, and the remaining space in the cavity, except for the portion occupied by the first molding portion 22, 34). &Lt; / RTI > Then, the liquid resin is cured to form the second molding portion 24 described above.

By the above processes, the first and second phosphors 32 and 34 can be regionally separated from the first and second molding portions 22 and 24. The formation of the air layer caused by the complicated shape in the cavity is suppressed by the above processes in which the first molding part 22 is formed first and the second molding part 24 is later formed, The occurrence of bubbles in the encapsulating material can be suppressed.

Hereinafter, other embodiments of the present invention will be described. The description overlapping with the description of the first embodiment is omitted in the following description of the embodiment.

3 is a cross-sectional view illustrating an LED package according to a second embodiment of the present invention. 3, the LED package 1 according to the present embodiment includes, in addition to the first and second molding parts 22 and 24 as a part of the encapsulating material, a resin molding part 23 for locally covering the LED chip 2 ).

Unlike the first embodiment, the second molding part 24 does not include a fluorescent material, but the second fluorescent material 34 is included in the resin part 23. The first molding part 22 includes a first phosphor 32 similar to that of the previous embodiment, and functions and roles of the first and second phosphors 32 and 34 are the same as those of the first embodiment. However, in the case of this embodiment, it is possible to concentrate the second phosphor 34 around the LED chip 2, to reduce waste of the phosphor, and to widen the distance between the first phosphor and the second phosphor.

4 is a cross-sectional view illustrating an LED package according to a third embodiment of the present invention. 4, the LED package 1 of the present embodiment includes, in addition to the first and second molding parts 22 and 24 as part of the sealing material, the first molding part 22 and the second molding part 22, 2 molding section 24. The third molding section 26 is formed on the upper side of the second molding section 24. [

Unlike the first embodiment, the second molding part 24 does not include a fluorescent material, and the third molding part 26 includes the second fluorescent material 34. The first molding part 22 includes a first phosphor 32 similar to that of the previous embodiment, and functions and roles of the first and second phosphors 32 and 34 are the same as those of the first embodiment. However, in the case of this embodiment, the distance between the first phosphor and the second phosphor can be further widened, and the degree of interference of the wavelength-converted light by the first phosphor 32 with the second phosphor 34 is reduced .

5 is a cross-sectional view illustrating an LED package according to a fourth embodiment of the present invention. 4, the LED package 1 according to the present embodiment includes, in addition to the encapsulant 20 including the first and second molding portions 22 and 24, an upper portion of the encapsulant 20 And a translucent film 40 attached to the upper surface of the molding portion 24).

In contrast to the first embodiment, the second molding part 24 does not include the fluorescent material, but the second fluorescent material 34 is included in the light transmitting film 40. The first molding part 22 includes a first phosphor 32 similar to that of the previous embodiment, and functions and roles of the first and second phosphors 32 and 34 are the same as those of the first embodiment.

6 is a cross-sectional view illustrating an LED package according to a fifth embodiment of the present invention. Unlike the previous embodiments, the LED package 1 of this embodiment has a property that the first molding portion 22 reflects light rather than transmitting light. For the reflection characteristic, the first molding part 22 is formed by a resin containing a reflective dye.

Accordingly, the first molding part 22 includes the inclined reflecting surface 221 in the inner periphery, and the first phosphors 32 are positioned on the reflecting surface 221 thereof. The light directed from the LED chip 2 to the first molding part 22 is reflected by the reflection surface 221 and is reflected by the first phosphor 32 positioned on the reflection surface 221, .

1 is a sectional view showing an LED package according to a first embodiment of the present invention;

FIG. 2 is a view for explaining a manufacturing process of the LED package shown in FIG. 1. FIG.

3 is a cross-sectional view of an LED package according to a second embodiment of the present invention.

4 is a cross-sectional view illustrating an LED package according to a third embodiment of the present invention;

5 is a sectional view showing an LED package according to a fourth embodiment of the present invention;

6 is a sectional view showing an LED package according to a fifth embodiment of the present invention;

FIG. 7 is a CIE 1931 chromaticity graph showing black body radiation curves together. FIG.

Claims

A package body having a cavity;

An LED chip mounted on a bottom surface of the cavity; And

An encapsulant disposed within the cavity and at least partially transparent,

Wherein the sealing material includes a second molding part including an annular first molding part including a first fluorescent material and a second fluorescent material having an excitation wavelength different from that of the first fluorescent material,

Wherein the first molding portion is spaced apart from the LED chip and disposed in contact with a side wall surface of the cavity,

Wherein at least a portion of the second molding portion is formed inside the first molding portion, and the LED chip and the first molding portion are sealed.

The method according to claim 1,

Wherein the second molding part includes a resin molding part covering the LED chip,

And the resin dipping portion includes the second phosphor.

A package body having a cavity;

An LED chip mounted on a bottom surface of the cavity; And

An encapsulant disposed within the cavity and at least partially transparent,

The encapsulant includes a third molding part including an annular first molding part including a first phosphor, a second molding part and a second phosphor different in excitation wavelength from the first phosphor,

Wherein the second molding part is translucent, at least a part of the second molding part is formed inside the first molding part to cover the LED chip,

And the third molding part is formed on the first molding part and the second molding part to seal the first molding part and the second molding part.

A package body having a cavity;

An LED chip mounted on a bottom surface of the cavity;

An encapsulant disposed in the cavity and at least partially transparent to light; And

And a translucent film attached to the top of the encapsulant,

Wherein the sealing material includes an annular first molding part and a second molding part including a first phosphor,

At least a part of the second molding part is formed inside the first molding part, and the LED chip and the first molding part are sealed

Wherein the translucent film comprises a second phosphor different in excitation wavelength from the first phosphor.

The LED package according to claim 1, wherein the LED chip is a blue LED chip, the first phosphor is a red phosphor, and the second phosphor is a yellow phosphor.

The LED package of claim 1, wherein the LED chip is a blue LED chip, the first phosphor is a red phosphor, and the second phosphor is a green phosphor.

The LED package according to any one of claims 1 to 4, wherein the sidewall surface of the cavity is a reflective surface inclined at a portion facing the annular molding portion.

The LED package according to any one of claims 1 to 4, wherein the first molding part is made of a reflective resin material and has an inclined reflection surface on an inner circumferential surface thereof.

delete