KR101251962B1

KR101251962B1 - LED package

Info

Publication number: KR101251962B1
Application number: KR1020110085159A
Authority: KR
Inventors: 김재건
Original assignee: 희성전자 주식회사
Priority date: 2011-08-25
Filing date: 2011-08-25
Publication date: 2013-04-08
Also published as: KR20130022251A

Abstract

The present invention relates to a light emitting diode package capable of improving luminance by improving light extraction efficiency for a specific wavelength, comprising: a mold frame in which a pair of lead electrodes are coupled and an accommodation space is formed therein; An LED chip mounted on the lead electrode on one side; A molding part filling the storage space while sealing the LED chip; And a wavelength conversion layer disposed above the molding portion.

Description

Light Emitting Diode Package {LED package}

The present invention relates to a light emitting diode package, and more particularly, to a light emitting diode package capable of improving luminance by improving light extraction efficiency for a specific wavelength.

Light emitting diodes (hereinafter referred to as LEDs) are light emitting devices made of semiconductors, which are more stable and reliable than other light emitting devices, and have a longer lifespan. In addition, since it can be driven by a voltage of several V and several tens of mA, the power consumption is small. Recently, an LED package capable of implementing white light or various colors has been developed, and its application field is gradually expanding. .

As a method of manufacturing a white light LED package, a combination of red, green, and blue LED chips causes white to appear or a combination of LED chips emitting a specific color and phosphors emitting a specific color. The white light LED package currently commercially used is mainly used in the latter way of sealing a resin in which yellow phosphor is dispersed in a blue LED chip. That is, the light generated from the blue LED chip and the yellow phosphor emits light of different wavelengths, and the two light having different wavelengths are mixed to output white light.

1 is a longitudinal cross-sectional view showing a LED package according to the prior art, Figure 2 is a graph showing the wavelength of light emitted from the LED package of FIG. As can be seen in FIG. 1, the LED package 10 has a pair of lead electrodes 12 coupled to a cup-shaped mold frame 11, and an LED chip mounted on one side of the lead electrodes 12 ( 13 is connected to the lead electrode 12 by a lead wire. In addition, a transparent resin in which the phosphor 15 is mixed is sealed in the inner space of the mold frame 11 on which the LED chip 13 is mounted to form the molding part 14.

In general, the LED chip 13, the molding part 14, and the air layer above the molding part have different refractive indices, and the light emitted from the LED chip 13 repeats total reflection at the upper and lower boundaries of the molding part 14. While exiting the upper air layer. At this time, most of the light emitted from the LED chip 13 is lost as heat during the total reflection process in the molding unit 14, and only a part of the light is emitted upward. That is, in the conventional LED package 10, since about 80% of the light emitted from the LED chip 13 is lost as heat, and only about 20% is emitted upward to contribute to light emission, light extraction efficiency is very low. .

In addition, the light emitted from the LED chip 13 passes through the molding unit 14 and is directly emitted upward or collides with the phosphor 15 and the wavelength is converted and emitted to have a wide range of wavelength bands. That is, as shown in FIG. 2, the conventional LED package 10 emits blue light of 470 nm wavelength, green light of 550 nm wavelength, and red light of 680 nm wavelength. In the light having three wavelength bands, white light is generated by mixing blue light of 470 nm wavelength and light of 550 nm wavelength band, but light of 680 nm wavelength band does not contribute to the appearance of white light and is extinguished. There is a problem.

The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a LED package that can improve the light emission efficiency by forming a pattern for inducing light emission on the surface of the molding part.

Another object of the present invention is to provide an LED package capable of improving luminance by improving light emission efficiency for light of a specific wavelength band substantially contributing to the appearance of white light.

The present invention for achieving the above object, a pair of lead electrodes are coupled, the mold frame is formed in the storage space therein; An LED chip mounted on the lead electrode on one side; A molding part filling the storage space while sealing the LED chip; And a wavelength conversion layer disposed above the molding portion.

The wavelength conversion layer may be disposed at a predetermined interval so as to secure an air layer between the molding parts, and a light scattering pattern is formed on at least one surface of the upper and lower surfaces. In addition, a light extraction pattern may be formed on the upper surface of the molding part.

According to the present invention having the structure as described above, by inducing the light emitted from the LED chip to the outside by the light extraction pattern formed on the surface of the molding part can improve the light output efficiency, in particular wavelength conversion disposed on the molding part The layer can improve the extraction efficiency of light in the wavelength band exhibiting white light, thereby improving the brightness of the LED package.

1 is a longitudinal sectional view showing an LED package according to the prior art;
2 is a graph showing the spectral characteristics of the light emitted from the LED package of FIG.
3 is a longitudinal sectional view showing an LED package according to an embodiment of the present invention;
4 is a graph showing the spectral characteristics of the light emitted from the LED package of FIG.
5 is a longitudinal sectional view showing an LED package according to another embodiment of the present invention, and
6 is a longitudinal cross-sectional view showing an LED package according to another embodiment of the present invention.

The technical problem achieved by the present invention and the practice of the present invention will be apparent from the preferred embodiments described below. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a longitudinal cross-sectional view showing an LED package according to an embodiment of the present invention, Figure 4 is a graph showing the spectral characteristics of the light for the LED package of FIG. As shown in Figure 3, the LED package 100 of the present invention is provided with a cup-shaped storage space on the upper side, a mold frame 110 is integrally coupled to a pair of lead electrodes 120 for power supply, The mold frame 110 is sealed on the LED chip 130 and LED chip 130 mounted on the lead electrode 120 on one side and connected to the lead electrode 120 by a lead wire to emit light having a predetermined wavelength. ) Is formed of a molding unit 140 to be filled in the storage space, a light extraction sheet 150 provided on the upper surface of the molding unit 140, and a wavelength conversion layer 160 disposed above the light extraction sheet 150. do.

Here, the mold frame 110 preferably inclines the side surface of the storage space at a predetermined angle in order to focus the light emitted from the LED chip 130 upward. In addition, a reflective layer may be formed on the bottom surface and the inclined surface of the storage space.

The LED chip 130 is a semiconductor device that converts electrical energy into light energy by a potential difference, and is connected to each lead electrode 120 by a lead wire.

The molding unit 140 seals the LED chip 130 and the lead wires to protect them from the outside and at the same time, phosphors are dispersed to convert the wavelength of light emitted from the LED chip 130. The molding part 140 is formed by curing a liquid resin in which phosphors are mixed with a transparent resin-based material such as an epoxy resin or a silicone resin.

In the LED package 100 having such a structure, the LED chip 130 generally has a refractive index of about 2.4, the molding part 140 has a refractive index of about 1.4, and the upper air layer has a refractive index of 1.0. Accordingly, the light emitted from the LED chip 130 is totally reflected at the upper and lower boundary surfaces of the molding part 140 by different refractive indices of the respective media and spreads to the entire interior of the molding part 140. In this process, some of the light is converted into heat inside the molding part and is extinguished, but some of the light is emitted upward through the upper boundary to contribute to light emission of the LED package. In addition, a part of the light emitted upward is emitted directly through the transparent resin, but part of the light is emitted at the converted wavelength by colliding with the phosphor.

In general, the LED package 100 of white light is mainly used for the LED chip 130 emitting blue, yellow phosphor is dispersed in the molding unit 140. Therefore, a part of the blue light emitted from the LED chip 130 is wavelength-converted to a relatively long wavelength yellow light by the phosphor, and mixed with the remaining short-wavelength light of the LED chip 130 to implement white light.

Meanwhile, in the present invention, the light extraction pattern 151 is provided to improve the light emission efficiency of the light emitted from the molding unit 140. Since the condition of total reflection inside the molding part 140 is narrowed by the light extraction pattern 151, the light emitted from the LED chip 130 and totally reflected by the molding part 140 is induced to be emitted to the outside. As shown, the light extraction pattern 151 may be formed on the upper surface of the sheet through the light extraction sheet 150 having excellent light transmittance, or may be directly formed on the upper surface of the molding part 140.

In addition, in the present invention, the wavelength conversion layer 160 for converting the wavelength of the light exiting the molding unit 140 is provided. The wavelength conversion layer 160 may be formed of a transparent material sheet having excellent light transmittance as shown, and may be disposed to form a predetermined distance d with the molding part 140 so that the air layer 170 is formed under the sheet. have. The light emitted from the molding unit 140 is mixed with light having various wavelengths between about 400 nm and 700 nm, and the wavelength conversion layer 160 allows light having a specific wavelength to be strongly emitted in the wavelength range. Specifically, the light emitted from the molding part 140 is emitted upward through the wavelength conversion layer 160 while repeating diffuse reflection and scattering in the air layer 170. At this time, the light passing through the wavelength conversion layer 160 is strongly emitted light having a specific wavelength band according to the Bragg's Law. That is, by disposing the wavelength conversion layer 160 on the molding unit 140, it can be adjusted so that light having a specific wavelength according to Bragg conditions is strongly emitted.

In addition, the light scattering pattern 161 is formed on the sheet of the wavelength conversion layer 160 so that light emitted from the molding unit 140 may be diffusely reflected and scattered in the air layer 170. ) May be formed on both the upper and lower surfaces of the sheet.

In the LED package 100 having the above structure, as shown in FIG. 4, light having a wavelength of approximately 470 nm and 550 nm is intensively emitted while passing through the wavelength conversion layer 160. That is, the wavelength conversion layer 160 converts the light of the wavelength that does not contribute to the appearance of the white light into the light of the wavelength that contributes to the appearance of the white light. As a result, the LED package may display white light having a relatively high luminance even with the same amount of light.

5 and 6 are longitudinal cross-sectional views illustrating an LED package according to another embodiment of the present invention. FIG. 5 illustrates another example of the wavelength conversion layer, and FIG. 6 illustrates another example of the molding part.

First, in the LED package 100 according to the embodiment of FIG. 5, the wavelength conversion layer 160 is directly formed on the upper surface of the light extraction pattern 151. The wavelength conversion layer 160 may be formed by molding and curing a transparent resin having excellent light transmittance on the upper surface of the light extraction pattern 151.

In addition, the LED package according to the embodiment of FIG. 6 may be configured to intervene the fluorescent film 142 on the upper surface of the molding unit 140 to emit light of different wavelengths. That is, the phosphor may be directly dispersed in the molding part 140 of the transparent resin to separate the wavelength in the molding part, or may be configured to separate the wavelength while passing through the fluorescent film through the upper surface of the molding part 140 of the transparent resin. . In this case, the fluorescent film 142 may be applied to the multi-fluorescence film partitioned into different fluorescent film by a predetermined area so that the light passing through can be separated into a plurality of different wavelengths.

Although the embodiments of the present invention have been described with reference to the present invention, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

100: LED package 110: mold frame
120: lead electrode 130: LED chip
140: Molding part
141: phosphor 142: fluorescent film
150: light extraction sheet 151: light extraction pattern
160: wavelength-changing layer 161: light scattering pattern
170: air layer

Claims

A mold frame having a pair of lead electrodes coupled thereto and having an accommodation space formed therein;
An LED chip mounted on the lead electrode on one side;
A molding part filling the storage space while sealing the LED chip; And
Including; a wavelength conversion layer disposed on the molding portion above,
The wavelength conversion layer is disposed at a predetermined interval so that an air layer is secured between the molding parts.
LED scattering pattern is formed on at least one surface of the upper and lower surfaces.

delete

The method of claim 1, wherein the molding part,
LED package, characterized in that the light extraction pattern is formed on the upper surface.