KR20090008818A

KR20090008818A - Surface mounting type light emitting diode device

Info

Publication number: KR20090008818A
Application number: KR20070072083A
Authority: KR
Inventors: 윤미정; 이선구
Original assignee: 삼성전기주식회사
Priority date: 2007-07-19
Filing date: 2007-07-19
Publication date: 2009-01-22
Also published as: KR100912442B1

Abstract

The present invention relates to a surface-mounted light emitting diode device, which is formed to have a lead frame having one or more pairs of lead terminals, and a radiation window opened to receive a portion of the lead frame therein and to emit light. A package comprising a cylindrical first space portion having an inner central portion in contact with the radiation window and a conical second space portion disposed thereunder, a reflective member coated on an inner wall of the second space portion of the package, and a second space of the package; Transparent resin filled in a flat portion, at least one LED chip mounted on the transparent resin so that a light emitting surface is directed toward the radiation window of the package, an electrode connection part for energizing the LED chip and the lead frame, and the package Provided is a surface-mounted light emitting diode device which is filled in a first space of the surface, and includes a molding material filled to surround the LED chip.

Description

Surface Mount Light Emitting Diode Device

The present invention relates to a light emitting diode device, and more particularly, to a surface mounted light emitting diode device that can improve the light extraction efficiency of the light emitting diode by preventing the disappearance of light emitted to the back of the LED chip while maintaining the color uniformity. It is about.

Light Emitting Diodes (hereinafter, referred to as LEDs) are semiconductor devices capable of realizing various colors of light by forming light emitting sources by changing compound semiconductor materials such as GaAs, AlGaAs, GaN, and InGaInP. Say.

In recent years, LED devices have been driven by the rapid development of semiconductor technology, so that they can escape from low-intensity general-purpose products and produce high-brightness and high-quality products. In addition, as the implementation of high-performance blue and white diodes becomes a reality, the application value of LEDs is being extended to displays, next-generation lighting sources, and the like. As an example, LED devices in the form of surface mounting devices have been commercialized.

Then, the surface-mount LED device according to the prior art will be described in detail with reference to FIGS. 1 and 2.

1 is a cross-sectional view showing the structure of a surface-mounted light emitting diode device according to the prior art, and FIG. 2 is a view showing a ray tracing result of FIG. 1.

First, referring to FIG. 2, the surface mount LED device according to the related art is formed of a synthetic resin material to accommodate a lead frame 50 formed of a pair of lead terminals and a portion of the lead frame 50 inside. The package 20, the LED chip 60 mounted vertically on the lead frame 50 inside the package 20, and a molding material filled in the package 20 to protect the LED chip 60 ( 85).

On the other hand, in general, the general criteria for determining the characteristics of the LED chip, such as color (color), brightness, intensity range of the brightness, etc., the characteristics of the LED chip is primarily determined by the material of the compound semiconductor used in the LED chip Incidentally, the structure of the package for mounting the LED chip is affected. In particular, the structure of such an LED package has a great influence on the angular distribution of luminance and luminance.

However, the light emitted from the LED chip 60 is emitted to all the top, bottom, left and right sides of the LED chip 60, as shown in FIG.

However, since the light emitted from the upper surface of the light emitted from the LED chip 60 is emitted relatively without loss, the light emitted from the lower surface is absorbed into the LED chip 60 and is extinguished. There is a problem in that the luminous intensity emitted after mounting in the package is lower than the luminous intensity emitted. In particular, referring to Figure 2 it can be seen that the loss of blue light of the light emitted from the LED chip is large.

That is, the surface mounted light emitting diode device according to the prior art has a problem that the light extraction efficiency of the LED chip is inferior.

In order to solve the above problems, the present invention provides a conical lower reflective structure in the package so that the bottom surface of the LED chip does not come into contact with the inner surface of the package, thereby minimizing the color coordinate difference of the light emitted from the LED chip. It is an object of the present invention to provide a surface-mounted light emitting diode device capable of preventing some from being absorbed, scattered and extinguished into the LED chip.

In order to achieve the above object, the present invention is formed to have a lead frame formed with one or more pair of lead terminals, and a radiation window opened to receive a portion of the lead frame, the light is emitted, the inside A package including a first cylindrical portion having a central portion in contact with the radiation window and a second cylindrical portion having a conical shape positioned below it, a reflective member coated on an inner wall of the second cavity portion of the package, and a second space portion of the package A transparent resin filled flatly, at least one LED chip mounted on the transparent resin so that a light emitting surface is directed toward the radiation window of the package, an electrode connection part for energizing the LED chip and the lead frame, and the package of the package Provided is a surface-mounted light emitting diode device filled in one space portion, the molding material filled to surround the LED chip.

In addition, in the surface mount light emitting diode device of the present invention, the molding material is preferably made of any one selected from a transparent epoxy, silicon or phosphor mixture, more specifically, the phosphor mixture is one of yellow, red, green It is preferable to include at least one phosphor that is wavelength-changed.

In addition, in the surface mounted light emitting diode device of the present invention, the LED chip is preferably made of a device for generating any one of the wavelength of blue, red, green, UV.

In addition, in the surface mounted light emitting diode device of the present invention, the inner wall of the conical second space portion is preferably coated with a reflective member.

In the surface mounted light emitting diode device of the present invention, the transparent resin is preferably made of transparent epoxy, silicon, modified silicone, urethane resin, oxetane resin, acrylic, polycarbonate, polyimide, and the like.

In addition, in the surface mounted light emitting diode device of the present invention, the electrode connection portion is preferably made of a wire for connecting the electrode of the LED chip and the lead terminal of the lead frame.

In addition, in the surface mounted light emitting diode device of the present invention, the inner wall of the cylindrical first space portion is preferably made of an inclined surface inclined such that the spherical surface adjacent to the radiation window is larger than the spherical surface contacting the second space portion.

In addition, in the surface mounted light emitting diode device of the present invention, the inner wall of the cylindrical first space is preferably coated with a reflective member.

Further, in the surface mount light emitting diode device of the present invention, it is preferable to further include a convex lens formed thereon to cover the cylindrical first space.

The present invention forms a conical bottom reflective structure in a package and mounts the LED chip on the bottom reflective structure so that the bottom thereof does not come into contact with the inner surface of the package, thereby minimizing the difference in color coordinates of the light emitted from the LED chip, while part of the light is inside the LED chip. As it can be blocked to be absorbed and scattered to disappear.

Therefore, the present invention has the effect of improving the light extraction efficiency while maintaining the color uniformity of the surface-mount type LED device.

Details of the technical configuration of the surface-mounted light emitting diode device of the present invention will be clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like parts throughout the specification.

Example

Hereinafter, the structure of the surface mounted LED device according to the embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4.

3 is a cross-sectional view illustrating a structure of a surface mounted light emitting diode device according to an exemplary embodiment of the present invention, and FIG. 4 is a diagram illustrating a ray tracing result of FIG. 3.

As shown in FIG. 3, the surface mounted light emitting diode device according to the present invention has a package 20 made of a molding epoxy resin or the like having a cavity formed in the center thereof, and a predetermined surface of the package 20 is formed of light. An open radiation window is formed so as to be easily radiated, and a lead frame 50 including a pair of lead terminals protrudes from the other surface to be mounted on the printed circuit board 10. In this embodiment, the lead frame 50 is composed of a pair of lead terminals as an example, but the present invention is not limited thereto, and lead terminals may be formed of two or more pairs.

In particular, the cavity formed in the center of the package 20 according to the present invention comprises a cylindrical first space portion 21 in contact with the radiation window and a conical second space portion 22 positioned below it.

More specifically, the inner wall of the first space portion 21 is formed as an inclined surface having a predetermined inclination angle such that the spherical surface adjacent to the radiation window is larger than the spherical surface in contact with the second space portion 22, the first space The inner wall of the portion 21 is preferably coated with a reflecting member (not shown) having a high reflectance.

On the other hand, the present invention, as shown in Figure 3 in order to reflect the light absorbed and scattered in the package 20 of the light emitted from the LED chip 60 through the reflective member back in the radiation window direction The inner sidewall structure of the first space portion 21 is not limited to a sidewall formed of an inclined surface, and may have sidewalls of various shapes such as a sidewall perpendicular to the outer bottom surface of the package and an elliptical sidewall. This is preferably adjusted according to the characteristics and process characteristics of the LED device and its conditions.

In addition, the inner space of the second space portion 22 is coated with the reflective member 90 to form a conical bottom reflective structure. At this time, the reflecting member 90 is made of a material having a high reflectance, and a material having a high reflectance includes Ag, Al, Ni, W, Cu, Pd, and Rh.

Meanwhile, in the present embodiment, the reflective member 90 is illustrated, but the present invention is not limited thereto, and the reflective member 90 may be omitted when the reflective member 90 may serve as a reflection in the package 20.

The second space part 22 having the inner wall coated with the reflective member 90 is flatly filled with the transparent resin 80. In this case, the transparent resin 80 may be made of a material such as transparent epoxy, silicone, modified silicone, urethane resin, oxetane resin, acrylic, polycarbonate and polyimide.

On the transparent resin 80 of the package 20 configured as described above, the LED chip 60 is mounted vertically toward the radiation window 40. The LED chip 60 is preferably made of a device for generating any one of blue, red, green, UV wavelength.

Therefore, the surface-mounted LED device according to the present invention emits light emitted from the LED chip 60 through the reflecting member 80 to the rear side and absorbs and scatters into the LED chip 60 to be extinguished. By reflecting back to the radiation window direction, it is possible to increase the light extraction efficiency than the surface-mounted LED device according to the prior art. This can be accurately understood with reference to Table 1 below. Also, FIG. 4 shows a ray tracing result of the surface mounted light emitting diode device according to the present invention, and a ray tracing result of the surface mounted light emitting diode device according to the related art. Comparing Figure 3 can be seen more accurately.

In addition, the surface mounted light emitting diode device according to the present invention is reflected through the reflective member 80 coated on the inner wall of the conical second space part 22, that is, the lower reflective structure formed under the LED chip 60. Since it is uniformly incident on the phosphor of the molding material to be described later to surround the LED chip 60, it is possible to minimize the difference in the color coordinates according to the viewing angle.

In particular, according to the present invention, since the second space portion 22 forming the lower reflective structure is formed in a conical shape rather than a hemispherical shape, similar light extraction efficiency can be obtained compared to the hemispherical shape, and the color coordinate difference can be reduced by about three times or more. It works.

This will be described in more detail through Table 1 below.

Referring to Table 1, it can be seen that the light extraction efficiency (%) is 29.7% without the lower reflection structure, while the light extraction efficiency (%) is higher with 35.5% when the lower reflection structure is present. Can be maintained at about the same level.

In addition, even if there is a lower reflecting structure, when the lower reflecting structure is a hemispherical shape and a conical shape according to the present invention, the light extraction efficiency (%) is almost the same as 36.3 (%) and 35.5 (%), but Δx of the color difference. It can be seen that Δy decreases from 0.048 to 0.019 by 0.03 to 0.024 by about three times.

In particular, the conical bottom reflective structure is omitted in comparison with the hemispherical bottom reflective structure, so that the manufacturing process is easy.

In addition, an electrode (not shown) of the LED chip 60 is electrically connected through a lead frame 50 formed of the pair of lead terminals and an electrode connection part 70, and in the present embodiment, the electrode connection part. A wire is used as 70.

The molding material 85 protecting the LED chip 60 is filled in the first space 21 of the package 20 in which the LED chip 60 is mounted. In this case, the molding material 85 may be made of a transparent epoxy, silicon, or phosphor mixture, and the like, wherein the phosphor mixture may include one or more phosphors whose wavelength is changed to one of yellow, red, and green. .

In addition, the surface-mounted light emitting diode device according to the present invention further includes a convex lens formed on the first space portion of the package, that is, on the radiation window, as shown in FIG. The light extraction efficiency may be further improved by minimizing the loss of light due to reflection due to the difference in refractive index between the molding material and the air layer on the upper surface of the molding material filled in the space.

5 is a cross-sectional view illustrating a structure of a surface mounted light emitting diode device according to a modification of the present invention.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

1 is a cross-sectional view showing the structure of a surface-mounted light emitting diode device according to the prior art.

FIG. 2 is a diagram illustrating a ray tracing result of FIG. 1. FIG.

3 is a cross-sectional view showing the structure of a surface-mount type light emitting diode device according to an embodiment of the present invention.

4 is a view showing the ray tracing results of FIG.

5 is a cross-sectional view showing the structure of a surface mount light emitting diode device according to a modification of the present invention.

10: printed circuit board 20: package

21: first space part 22: second space part

50: lead frame 60: LED chip

70 electrode connection portion 80 transparent resin

85: molding material 90: reflective member

100: convex lens

Claims

A lead frame in which at least one pair of lead terminals is formed;

A part of the lead frame is accommodated therein, and is formed to have a radiation window opened to emit light, and an inner central portion includes a cylindrical first space portion contacting the radiation window and a second cone space portion positioned below it. package;

Transparent resin flatly filled in the second space portion of the package;

One or more LED chips mounted on the transparent resin such that a light emitting surface faces a radiation window of the package;

An electrode connection part for energizing the LED chip and the lead frame; And

And a molding material filled in the first space of the package and filled to surround the LED chip.

The method of claim 1,

The molding material is a surface-mount light emitting diode device, characterized in that made of any one selected from a transparent epoxy, silicon or phosphor mixture.

The method of claim 2,

The phosphor mixture is a surface-mounted light emitting diode device, characterized in that it comprises one or more phosphors of which wavelength is changed to any one of yellow, red, green.

The method of claim 1,

The LED chip is a surface-mount LED device, characterized in that consisting of a device for generating any one of the wavelength of blue, red, green, UV.

The method of claim 1,

An inner wall of the conical second space portion is coated with a reflective member, characterized in that the surface mounted light emitting diode device.

The method of claim 1,

The transparent resin is a surface-mounted light emitting diode device, characterized in that made of any one of a transparent epoxy, silicon, modified silicone, urethane resin, oxetane resin, acrylic, polycarbonate and polyimide.

The method of claim 1,

The electrode connector is a surface-mount LED device, characterized in that made of a wire for connecting the electrode of the LED chip and the lead terminal of the lead frame.

The method of claim 1,

The inner wall of the cylindrical first space portion is a surface-mounted light emitting diode device, characterized in that the inclined surface inclined so that the spherical surface adjacent to the radiation window is larger than the spherical surface in contact with the second space portion.

The method of claim 1,

The inner wall of the cylindrical first space portion is a surface-mount light emitting diode device, characterized in that coated with a reflective member.

The method of claim 1,

And a convex lens formed thereon to cover the cylindrical first space.