KR20050103625A - Led package for use in back-light unit - Google Patents

Abstract

A light emitting diode package for a backlight is disclosed. The backlight LED package for the backlight is provided with a reflector surrounded in all directions, the lower part of which is exposed to the bottom of the reflector to perform power input and heat dissipation functions, and R, G, B tricolor chips on the upper surface thereof. These lead plates are mounted, and the lead plates are disposed at a distance from the lead plates, and a lower portion thereof includes electrode terminals exposed to the bottom of the reflector and to which power is input, and emitted from the R, G, and B chips. The light is mixed in the reflector to form white light, and is emitted at a wider side on the long side of the package and at a narrower angle on the short side to form white light, which is incident on the light guide plate.

Description

LED package for backlight {LED PACKAGE FOR USE IN BACK-LIGHT UNIT}

The present invention relates to a light emitting diode package for backlight, and more particularly, by mounting the R, G, B tricolor chips in the same package and improving the structure, it is possible to reduce the light mixing distance while achieving an orientation angle advantageous to the light guide plate incident. The present invention relates to a light emitting diode package for a backlight that can improve heat dissipation effect and reliability.

In general, a liquid crystal display device injects liquid crystal between two glass plates and applies power to electrodes provided on the upper and lower glass plates to change liquid crystal molecular arrays in each pixel, and to display an image. The liquid crystal display device includes a panel unit, a driver unit, and a backlight unit.

Such a liquid crystal display itself is non-luminous and thus cannot be used where there is no light. Due to this problem, a device for uniformly irradiating an information display surface for the purpose of enabling use in a dark place is a backlight unit.

The backlight unit includes a light guide plate and a light source. The light source is generally arranged to inject light into the light guide plate from the side of the light guide plate, and mainly uses a CCFL (cold cathode tube), but in recent years, it has a long life and a separate inverter. Advantageously, light emitting diodes that do not require the same are preferred. In particular, the use of light-emitting diodes as a light source of high-definition products is required because of the advantages of excellent color clarity, including all three primary colors of R, G, and B.

Application of the liquid crystal display backlight light source of the light emitting diode is arranged in plurality along the side of the light guide plate to generate the optimum light efficiency with the minimum number of light emitting diodes in consideration of economic efficiency in determining the quantity of the light emitting diode to secure the required luminous intensity.

Such an arrangement may achieve high light efficiency by bringing the light emitting diodes into close contact with the light guide plate, but the light emitting diodes should be spaced a certain distance from the light guide plate to achieve a uniformly uniform white light distribution mixed and mixed in the light guide plate.

This gap eventually lowers the light efficiency, requiring more light emitting diodes to be disposed, and increasing the outer size of the liquid crystal display panel.

On the contrary, in order to reduce the play, the light emitting diode has a duality in which the light emitting diode more than necessary is closely disposed due to the uniform light distribution in the light guide plate.

On the other hand, the light emitting diode chip should be packaged in a usable form, and the gap between the light guide plate and the light distribution in the light guide plate can be improved according to the package design.

This is because the light efficiency and directivity of the light emitting diodes can be adjusted according to the shape and material of the package. In other words, it is necessary to design a package that reduces the gap with the light guide plate and reduces the number of arrangement of the light emitting diodes while increasing light mixing and light efficiency.

A wider direct angle is required for light mixing with neighboring packages within a small gap with the light guide plate, but a narrower angle is required to increase the efficiency of the incident light and the incident light in the light guide plate.

In this regard, it is preferable that the divergent light of the light emitting diode through the package has a wide direction angle for the length of the light guide plate and a narrow direction angle for the axis for the thickness of the light guide plate. This is due to the fact that the directivity characteristic for a constant luminous flux is inversely proportional to the luminous intensity.

Figure 1 (a) shows an example of such a light emitting diode package. As shown, each package 3a, 3b, 3c representing the colors of red (R), green (G), blue (B) is provided in a separate package form on the case (2) in a certain order Arrange with.

Each of the R, G, and B packages 3a, 3b, and 3c includes light emitting diode chips (not shown), and the light emitted from the light emitting diode chips is incident on the light guide plate 1 to irradiate the liquid crystal panel. do.

At this time, since the light emitted from each package 3 maintains the directivity angle θ1 at a predetermined angle in the X-axis direction and proceeds at a predetermined distance d1, the tricolor light is mixed with each other at a predetermined point P. Is converted to.

Therefore, the light converted into white light may pass through the light guide plate 1 to irradiate the liquid crystal panel to have a predetermined brightness and luminous intensity.

However, such a conventional LED package for backlight emits light from each light emitting diode, and after reaching a certain distance, each light is mixed with each other and converted into white light, thereby increasing the light mixing distance, thereby increasing the size of the backlight unit. There is a problem.

In addition, since the light emitted from the package 3 has a narrow orientation angle, dark spot phenomenon occurs.

As shown in FIG. 1B, when the light directing angle θ2 of the Y axis of the light emitted from the light emitting diodes 3 is large, there is a problem in that a hot spot occurs in the first half of the panel.

In addition, the conventional LED package has a problem of increasing the size of the backlight by having a relatively large body, such as pin type, hook type, J type.

On the other hand, as a prior art in the technical field published by the Patent Publication No. 2003-0097574 (published number) filed by Advanced Optoelectronics Technology, in the present invention, the first light emitting diode crystal grains, the second light emitting diode crystal particles and the third A light emitting diode package including light emitting diode crystal grains is provided.

In addition, Patent Application No. 2001-0064820 (Publication No.) filed by Kochi Kopati provides a side emitting type LED lamp with uniform directivity, less misalignment between LED elements, and miniaturization.

However, even in such a prior art, there is still a problem that the size of the package and the light mixing distance increase, and a hot spot phenomenon occurs.

Accordingly, an object of the present invention has been proposed to solve the above problems, and an object of the present invention is to provide a light emitting diode package for a backlight which can minimize the mixing distance of the tricolor light by providing a tricolor chip in a single package.

In addition, another object of the present invention is to provide a light emitting diode package for a backlight that can minimize the thickness of the light guide plate by reducing the size by applying a leadless type of package.

Further, the present invention provides a backlight LED package for increasing the heat dissipation effect and improving reliability by protruding the heat sink to the outside by using a half etching technique.

The present invention also provides a light emitting diode package for a backlight which can prevent the occurrence of hot spots and dark points occurring in the liquid crystal panel by adjusting the orientation angle of the package.

In order to realize the object of the present invention mentioned above, the present invention comprises a reflector of the shape surrounded in all directions; A lead plate provided at the reflector, the lower portion of which is exposed at the bottom of the reflector to perform power input and heat dissipation functions, and a three-color chip of R, G, and B is mounted on an upper surface thereof; The lead plate is disposed at a distance from the lead plate, and a lower portion thereof includes an electrode terminal exposed to a bottom of the reflector to receive power, and tricolor light emitted from the R, G, and B chips is mixed in the reflector. The light emitting diode package for a backlight is formed to form white light, and is emitted at a wider side of the package and a narrower direction angle at the short side to form white light.

Hereinafter, a backlight LED package according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 and 3, the LED package 10 for backlight according to the present invention is disposed on one side of the light guide plate 12 to perform a function as a light source.

That is, the plurality of light emitting diode packages 10 arranged in a row on the case 20 respectively emit white light when power is applied, and the emitted light is incident on the light guide plate 12 to reflect the plate 14 and the diffusion sheet 16. ) And the like are supplied to the liquid crystal panel 18.

As shown in FIGS. 4 to 6, the light emitting diode packages 10 are positioned in a state surrounded by reflectors 22 formed of four X- and Y-axis reflectors 40 and 42, respectively. .

The lead plate 24 is molded and fixed inside of the reflector 22. R, G, and B tricolor chips 26a, 26b, and 26c are mounted on the lead plate 24, respectively.

The electrode terminals 28a, 28b, and 28c fixed to the reflector 22 are connected to the corresponding chips 26a, 26b, and 26c, respectively.

In the backlight LED package having such a structure, the reflector 22 is molded to have a substantially hexahedral shape by a molding method.

The R, G, and B tricolor chips 26a, 26b, and 26c are 450 to 480 nm for the blue chip 26a, 500 to 530 nm for the green chip 26b, and 600 for the red chip 26c. Chips emitting light in the wavelength region of -635 nm are used.

In addition, the R, G, and B tricolor chips 26a, 26b, and 26c are arranged in the same space surrounded by the reflector 22. Accordingly, the light emitted from the R, G, and B tricolor chips 26a, 26b, and 26c may be mixed with each other within a short distance to form white light at a predetermined point P (FIG. 7) to be incident on the light guide plate 12. .

As a result, the light mixing distance D1 of the light emitting diode 26 to implement white light can be reduced, thereby miniaturizing the size of the backlight unit.

4, 7 and 8, the reflector 22 is perpendicular to the X-axis reflector 40 and the X-axis reflector 40 for controlling the X-axis direction angle θ2 of light. The Y-axis reflector 42 is formed to control the Y-axis direction angle θ1 of the light.

In these X-axis and Y-axis reflectors 40, 42, the height of the X-axis reflector 40 is formed low, and the height of the Y-axis reflector 42 is formed high.

Therefore, when light is emitted from the tricolor chips 26a, 26b, and 26c as shown in FIG. 7, the light is formed with a lower height of the X-axis reflector 40, so that the light is wider in the X-axis direction, that is, the longer side. By diverging, the X-axis orientation angle (?? 2) can be further expanded. As a result, the light enlarged in the X-axis direction is incident to the light guide plate 12 and supplied to the liquid crystal panel, thereby preventing generation of dark spots that may occur in the liquid crystal panel.

In addition, since the X-axis direction angle θ2 is widened, the area of the light guide portion 12 which the LED package 10 is responsible for is widened, so that the distance D2 between the light emitting diodes 26 can be widened. The number of diodes 26 can be reduced.

In addition, the height of the Y-axis reflector 42 is formed to be relatively low so that the light emitted from the light emitting diode 26 proceeds while maintaining the Y-axis direction angle θ1 of a narrow angle in the Y-axis direction, that is, the short side.

That is, as shown in FIG. 8, when light is emitted from the light emitting diodes 26, the emitted light is reflected through the narrowly formed Y-axis reflector 42 to be incident in the vertical direction with respect to the light guide plate 12. In this case, the Y-axis direction angle θ1 of the light may be reduced.

Therefore, when the Y-axis orientation angle θ1 is wide, hot spots that may occur in the first half of the liquid crystal panel may be prevented.

In addition, as shown in FIG. 10, X- and Y-axis reflectors 62 and 64 which function as reflectors are formed inside the package 60, and the X- and Y-axis reflectors 62 and 64 are formed. By controlling the inclination of the inner surface, such a hot spot phenomenon can be prevented.

That is, by forming the inner inclination of the two reflectors (62, 64) differently, it is possible to effectively control the light incident on the light guide plate when the light emitted from the light emitting diode 66 is reflected inside the reflectors (62, 64) have.

Meanwhile, the lead plate 24 on which the R, G, and B tricolor chips 26a, 26b, and 26c are mounted is a leadless type lead plate 24 as shown in FIGS. 4 and 5. Is applied.

In other words, the end of the lead plate 24 is manufactured by cutting with a tool such as a diamond blade without protruding to the outside of the reflector 22. Therefore, the end of the lead plate 24 does not protrude to the outside, thereby reducing the size.

In addition, the lower parts 34 and 36 of the lead plate 24 and the lower parts 30a, 30b and 30c of the electrode terminals 28a, 28b and 28c are etched by half etching, respectively, so that the reflector 22 is etched. ) Can be exposed to the outside.

That is, one side lower portion of the lead plate 24 is exposed to the bottom portion 23 of the reflector 22 by an etching method to form the auxiliary electrode terminal 36, and the middle portion forms the heat sink 34. The lower portions 30a, 30b, and 30c of the electrode terminals 28a, 28b, and 28c are also etched to expose the bottom of the reflector 22 so that external power can be input.

As a result, all the rear surfaces of the lead frame except for the etched surface and the injection reflector are exposed and the sides are locked to the exit surface.

In addition, the electrode terminals 28a, 28b, and 28c and the lead plate 24 are electrically connected to each other by the wire 32.

Accordingly, power is applied through the electrode terminals 28a, 28b, and 28c and the auxiliary electrode terminal 36, thereby causing the light emitting diode 26 to emit light.

The light emitting diode package 10 etched by the half etching method as described above can enhance the adhesive force with the inner pad 38 and can effectively block the inflow of micro cracks or moisture, thereby improving reliability.

On the other hand, Figure 9 shows a different implementation of the size of the R, G, B tricolor chips (52, 54, 56) as another preferred embodiment of the present invention.

That is, each of the chips 52, 54, 56 of R, G, and B has different light outputs according to its specifications. Therefore, in order to implement a white color having good color reproducibility, it is required to change the specifications of the chip so that the light output suitable for the white implementation can be output for each chip 52, 54, 56.

Therefore, as another embodiment of the present invention by forming the size of each of the chips of R, G, B differently, the light output is different from each other. Due to such a difference in light output, it is possible to easily implement white light.

As described above, the light emitting diode for backlight according to the preferred embodiment of the present invention has the following advantages.

First, the R, G, B tricolor chip is provided in a single package, thereby minimizing the light mixing distance of the tricolor light.

Second, there is an advantage in that the thickness of the light guide can be minimized by reducing the size by applying a leadless type package.

Third, there is an advantage of increasing the heat dissipation effect and improving reliability by protruding the heat sink to the outside using the half etching technique.

Fourth, there is an advantage that it is possible to prevent the occurrence of hot spots and dark points occurring in the liquid crystal panel by adjusting the orientation angle of the X-axis and Y-axis of the package.

Fifth, the manufacturing process is simple, the productivity can be increased, and by adjusting the light directing characteristics, there is an advantage of obtaining the sum of colors and even luminance.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it is within the scope of the present invention.

1 (a) and 1 (b) are views for showing a light mixing distance and a light directing angle of a backlight LED package according to the prior art;

2 is an exploded perspective view showing a light emitting diode package for a backlight according to a preferred embodiment of the present invention;

3 is a side view of FIG. 2;

4 is an enlarged perspective view of the light emitting diode package shown in FIG.

Fig. 5 is a sectional view showing a section along the "A-A" line in Fig. 4;

Figure 6 is a bottom view of Figure 4;

FIG. 7 is a view for showing light mixing distance and hot spot generation of the LED package for backlight shown in FIG. 2; FIG.

FIG. 8 is a view for showing a light directing angle of the LED package for backlight shown in FIG. 2; FIG.

Fig. 9 is a perspective view showing a light emitting diode package mounted with chips having different sizes according to another preferred embodiment of the present invention.

Fig. 10 is a perspective view showing a light emitting diode package in which the inner side slopes of the reflector are formed differently according to another preferred embodiment of the present invention.

Claims (7)

A reflector having a shape surrounded in all directions; A lead plate provided at the reflector, the lower portion of which is exposed at the bottom of the reflector to perform power input and heat dissipation functions, and a three-color chip of R, G, and B is mounted on an upper surface thereof; And The lead plate is disposed away from the lead plate by a predetermined distance, and a lower portion thereof includes an electrode terminal exposed to a bottom of the reflector to receive power. The tricolor light emitted from the R, G, and B chips is mixed inside the reflector to form white light, and is wider on the long side and shorter on the short side, and is emitted at a narrower angle to form white light, which is incident on the light guide plate. . The method of claim 1, wherein the reflector is formed in an orthogonal direction of the X-axis reflector and the X-axis reflector for extending the direction angle of the long side (X-axis direction) and formed higher than the X-axis reflector of the short side (Y-axis direction) A light emitting diode package for a backlight comprising a Y-axis reflector which reduces the directivity angle. The LED package of claim 1, wherein each end of the lead plate includes a leadless method to prevent protruding from the outside of the reflector. The backlight LED of claim 1, wherein a lower portion of the lead plate is exposed to a bottom of the reflector to form an auxiliary electrode terminal and a heat sink, and a lower portion of the electrode terminal is exposed to a bottom of the reflector to enable power input. . The LED package of claim 4, wherein the lead plate and the electrode terminal are etched by a half etching method. The backlight LED package of claim 1, wherein the amount of light output can be easily adjusted by forming different sizes of the tricolor chips. The LED package of claim 1, wherein inner surfaces of the reflectors are formed to have different inclinations.