KR101285311B1 - LED package and back light unit - Google Patents

Abstract

The present invention provides a LED package and a backlight unit having high heat dissipation characteristics and luminous efficiency, and includes a first pad having a first surface in a first direction and a second surface in a second direction opposite to the first direction; And a second pad electrically separated from the first pad, the second pad having a third surface in the first direction and a fourth surface in the second direction, and fixing the first pad and the second pad to the first direction. A molding part having a first opening exposing at least a portion of the first and third surfaces, respectively, and a second opening exposing at least a portion of the second and fourth surfaces in the second direction; A light emitting diode chip seated on a first surface of one pad and electrically connected to the first pad and the second pad and emitting light; a first lead electrically connected to the first pad and positioned outside the molding part; Electrically connected to the second pad and connected to the first lead. Is separated and relates to a light emitting diode package and a backlight unit including a second lead positioned outside the molding part.

Description

LED package and back light unit

The present invention relates to a light emitting diode package and a backlight unit, and more particularly, to a light emitting diode package and a backlight unit that can further improve heat dissipation efficiency.

Light emitting diodes (hereinafter referred to as LEDs) are devices that convert electricity into light using characteristics of compound semiconductors, and are being used and developed in various ways as next generation lighting sources.

Such LEDs are packaged by molding parts and lead frames and used as LED packages, and have been recently developed for various displays. In particular, many LEDs have been researched and developed as backlight units of liquid crystal displays.

These LED packages can be roughly classified into top-view type LED and side-emitting LED packages depending on whether the light is projected upwards or sideways of the connected structure. In the case of a backlight unit employed in a large area liquid crystal display device, a top-view type LED package is adopted to obtain high output. However, in this case, when the LED packages are arranged along the side incident surface of the light guide plate, the PCB on which the LED packages are mounted should be erected to be parallel to the incident surface of the light guide plate, thus requiring a separate aluminum chassis or bracket for this purpose. Therefore, the required parts increase, which results in a complicated structure. In addition, there is a problem that the heat resistance is increased by forming an air gap of the connection part due to an increase in required parts, thereby degrading the performance of the entire backlight unit.

Side-emitting type LED package is widely used in the backlight unit for small displays used in electronic communication devices such as mobile phones and PDAs. To be used for a TV, the output must be high and the heat dissipation function is also required. However, since the conventional side-emitting type LED package has a structure suitable for use for a small display as described above, when it is increased to a high output, heat dissipation characteristics are not secured, and thus there is a limit that is difficult to use in a TV.

The present invention is to overcome the above problems and the limitations of the prior art including the same, and an object of the present invention is to provide an LED package and a backlight unit having higher heat dissipation characteristics.

Another object of the present invention is to provide an LED package and a backlight unit having a higher luminous efficiency.

In order to achieve the above object, the present invention provides a first pad having a first surface facing in a first direction and a second surface facing in a second direction opposite to the first direction, and electrically separated from the first pad. And a second pad having a third surface facing the first direction and a fourth surface facing the second direction, and fixing the first pad and the second pad and having a supporting surface to face the first direction. A molding part having a first opening exposing at least a portion of the first and third surfaces, respectively, and a second opening exposing at least a portion of the second and fourth surfaces in the second direction; A light emitting diode chip seated on a first surface of the pad and electrically connected to the first pad and the second pad and emitting light; a first lead electrically connected to the first pad and positioned outside the molding part; Electrically connected to a second pad and separated from the first lead, A light emitting diode package including a second lead positioned outside the negative portion, wherein the sum of the area of the lower surface of the first lead and the area of the lower surface of the second lead is 30% or more and 100% or less of the area of the support surface. do.

The first lead and the second lead may extend to be perpendicular to the first and third surfaces of the first pad and the second pad, respectively.

Unevenness may be formed in at least one of the second surface of the first pad and the fourth surface of the second pad exposed through at least the second opening.

The light emitting diode chip of the first pad may be formed on a first surface on which the light emitting diode chip is seated, and may further include a reflecting surface provided to surround the light emitting diode chip.

The present invention also includes a main body, a light guide plate positioned on the main body, a PCB mounted on the main body, and the above-described LED package mounted on the PC and arranged to align with a light incident part of the light guide plate. Provide a backlight unit.

The PC may be a metal PCB.

It may further include a heat conductive layer interposed between the body and the PC.

The light incident portion of the light guide plate may be a side surface of the light guide plate, and the PC ratio may extend between the light guide plate and the main body.

A first lead and a second lead of the LED package may be bonded to the PC, and a line connecting the centers of the first and second openings may be parallel to the surface of the PC.

According to the present invention made as described above, it is possible to provide an LED package and a backlight unit with higher heat dissipation characteristics.

In addition, it is possible to provide an LED package and a backlight unit having higher luminous efficiency.

Accordingly, even in the case of the side-emitting LED package, it can be easily applied to a backlight unit requiring a high output of 0.25W or more.

In addition, since there is no need for a separate chassis or bracket for mounting the LED package according to the present invention it is more advantageous in terms of assembly, productivity, cost.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the embodiments described below, the same reference numerals are used for the components having the same names.

1 is a front view illustrating a light emitting diode package 100 according to an exemplary embodiment of the present invention, and FIG. 2 is a bottom view of the light emitting diode package of FIG. 1. 3 is a cross-sectional view taken along line III-III of FIG. 1, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 1.

The light emitting diode package 100 according to the preferred embodiment of the present invention is a side light emitting diode package.

In the drawing, the X-axis direction is a direction in which light is emitted from the first chip 108, which is an LED chip, and the Z-axis direction is a direction in which the LED package of the present invention is mounted on the PC. In the following description, for convenience of description, the surface in the Z-axis direction is a lower surface, the surface in the direction opposite to the Z-axis is the upper surface, the surface in the Y-axis direction is the side, and the surface in the X-axis direction is described in front. do.

According to the drawing, the LED package 100 according to the present embodiment includes a first pad 104 and a second pad 105 separated from each other, a first chip 108, a molding unit 101, and a first pad 104. One lead 106 and a second lead 107.

The first pad 104 and the second pad 105 are preferably formed of a conductive metal plate member, and have a structure that is spaced apart from each other and electrically separated from each other.

The first pad 104 has a first surface 104a that is an upper surface in a first direction (X-axis direction) and a second surface 104b that is a lower surface in a second direction (-X-axis direction). The second pad 105 also has a third surface 105a that is an upper surface in the first direction and a fourth surface 105b that is a lower surface in the second direction.

The first chip 108 is mounted on the first pad 104. In particular, the first chip 108 is mounted on the first surface 104a of the first pad 104, and the first chip 108 of the first surface 104a on which the first chip 108 is mounted. The first reflecting surface 104c may be formed around the. The first reflecting surface 104c is formed by bending the first pad 104 in the second direction (-X axis direction), and is inclined at a predetermined angle to diverge from the first chip 108 toward the side surface. The extracted light is directed in the first direction (X-axis direction) to improve light extraction efficiency.

The first chip 108 may be an LED chip, and may be die bonded through a die adhesive inside the first pad 104, particularly, the first reflection surface 104c. . The first chip 108 may be electrically connected to the first pad 104 and the second pad 105 by the first wire 109 and the second wire 110, respectively. The first chip 108 and the first pad 104 and the second pad 105 are not necessarily connected by wires, but may be connected without wires by a flip chip bonding method. The plurality of first chips 108 may be mounted.

The first pad 104 and the second pad 105 are fixed by the molding part 101. The molding part 101 is formed by a resin material or the like by transfer molding or injection molding. The molding part 101 supports and fixes the first pad 104 and the second pad 105. The molding part 101 forms an outline of the LED package 100.

The molding part 101 has a first opening 102 and a second direction (-) exposing at least a portion of the first surface 104a and the third surface 105a in a first direction (X-axis direction), respectively. And a second opening 114 exposing at least a portion of the second surface 104b and the fourth surface 105b in the X-axis direction). Parallel lines connecting the centers of the first openings 102 and the second openings 114 are parallel to the surface of the PC 400 on which the LED package 100 of the present invention is mounted, as shown in FIG. It may flow into the second opening 114.

1 to 4 illustrate that the second opening 114 exposes only the second surface 104b, but the present invention is not limited thereto, and the second opening 114 is further limited. Of course, it may be wider to expose a part of the fourth surface 105b together.

The molding part 101 allows the light emitted from the first chip 108 to be emitted through the first opening 102, and the second of the first pad 104 through the second opening 114. By exposing the surface 104b and / or the fourth surface 105b of the second pad 105 to air, the heat emitted from the first chip 108 can be easily released, thereby further improving heat dissipation efficiency. . In particular, since the outside air flows into the molding part 101 through the second opening 114, the heat dissipation effect can be further maximized.

The molding part 101 may be provided to form a second reflecting surface 102a around the first chip 108. As shown in FIGS. 3 and 4, the second reflecting surface 102a is disposed to be inclined to extract more light emitted from the first chip 108 in the front direction, and the inner surface thereof is inclined with respect to the front direction. It is preferable to have an angle of 52 to 88 degrees outward. Accordingly, more light can be extracted in the direction of the light guide plate, and the direction of the right and left direction is maximized to minimize the bezel width of the set by minimizing the dark portion between the LED packages when forming the backlight unit.

As shown in FIGS. 3 and 4, an additional sealing member 115 may be further formed inside the second reflection surface 102a to protect the first chip 108 from the outside. Phosphors are mixed in the sealing material 115 to adjust the color of light emitted from the first chip 108.

The molding portion 101 is mounted on a PCB (Printed Circuit Board) (PCB), the lower surface of which is described below. In this case, the entire surface projected toward the PCB, for example, is defined as the supporting surface 101a.

Meanwhile, the first lead 106 and the second lead 107 extend from the first pad 104 and the second pad 105 to be exposed to the outside of the molding part 101. The first lead 106 and the second lead 107 are electrically connected to the first pad 104 and the second pad 105, respectively, and are integral with the first pad 104 and the second pad 105, respectively. It is desirable to form a.

These first leads 106 and second leads 107 are formed in a plate shape as shown in FIG. 2 and extend along the support surface 101a. Accordingly, the first lead 106 and the second lead 107 may be substantially perpendicular to the first surface 104a of the first pad 104 and the third surface 105a of the second pad 105. It is extended.

The first lead 106 and the second lead 107 each have bottom surfaces 106a and 107a that are wide surfaces. In one embodiment of the present invention, the sum of the areas of the lower surfaces 106a and 107a of the first and second leads 106 and 107 is equal to or greater than 30% of the area of the support surface 101a. It should be less than or equal to%. The larger the size of the first lead 106 and the second lead 107, the better. However, it is preferable that the size of the first lead 106 and the second lead 107 be 30% or more and 100% or less of the area of the support surface 101a for productivity and workability.

Thus, when the first lead 106 and the second lead 107 are formed in a relatively large area, the first lead 106 and the second lead having a large area may be used even when a high output LED chip is used as the first chip 108. Through heat dissipation 107 can be effectively achieved. To this end, the first lead 106 and the second lead 107 may be mounted on the PC 400 as shown in FIG. 6 so that heat transfer may be smoothly performed through the PC 400. Accordingly, as shown in FIGS. 1 to 4, even when a high power LED chip is used in the side-emitting type LED package 100, the heat dissipation function can be sufficiently secured, and thus it can be used for a TV.

In the present invention, the first lead 106 and the second lead 107 extend in the extending direction of the support surface 101a of the molding portion 101 as described above, and the first lead 106 and A support 103 is provided between the second leads 107 to prevent short between leads and to balance the entire package. As shown in FIG. 3, the support 103 may be provided to be inclined toward the rear surface rather than being flat. However, the present invention is not limited thereto and may be provided flat.

Meanwhile, as shown in FIG. 5, the unevenness 104d may be further formed in the portion of the second surface 104b of the first pad 104 exposed through the second opening 114 of the molding part 101. have. The unevenness 104d increases the area where the second surface 104b comes into contact with the outside air, thereby maximizing heat dissipation efficiency.

If a part of the fourth surface 105b of the second pad 105 is exposed through the second opening 114, the above-described unevenness may be formed in the exposed portion.

Meanwhile, as shown in FIG. 1, the second chip 113 may be further seated on the second pad 105. The second chip 113 may be a zener diode chip or the like for protecting the first chip 108 from static electricity. The second chip 113 is electrically connected to the second pad 105, and is also electrically connected to the first pad 104 through the third wire 111.

According to an embodiment of the present invention, as shown in FIG. 4, the second pad 105 may prevent the brightness of light emitted from the first chip 108 from being lowered by the second chip 113. The second chip 113 may be disposed in the lead portion 112. Accordingly, the light emitted from the first chip 108 may be minimized by the second chip 113. It is preferable that the drawn depth of the inlet part 112 corresponds to the thickness of the second chip 113, but is not necessarily limited thereto. The protruding thickness of the second chip 113 seated on the inlet part 112 is not limited thereto. Therefore, the depth enough to prevent the optical characteristics of the first chip 108 from being affected is sufficient.

The LED package 100 formed as described above may be mounted in the backlight unit as shown in FIG. 6.

The backlight unit according to the exemplary embodiment of the present invention includes a main body 200, a light guide plate 300, a PCB 400, and an LED package 100.

The light guide plate 300 is mounted to the main body 200 such that the lower surface of FIG. 6, the wide surface of the light guide plate 300, faces the main body 200.

The PCB 400 preferably uses a metal PCB. Accordingly, heat generated from the LED package 100 may be effectively transferred to the main body 200 via the PCB 400. The PCB 400 may be formed to be wider to pass through the light incident portion of the light guide plate 300, and thus, the light reflected from the light incident portion of the light guide plate 300 may be reflected again as much as possible to increase efficiency. To this end, as the PCB 400, a high reflectance PSR and an insulator having a thermal conductivity of 1 to 2 W / mK are used. However, the PCB 400 is not necessarily limited to a metal PCB, but a general PCB may be used, and a FPCB (Felxible Printed Circuit Board) may also be applied.

The PCB 400 mounted with the LED package 100 is disposed along the edge of the light guide plate 300, that is, along the light incident part of the side surface of the light guide plate 300. In this case, the PCB 400 may be formed by mounting a large area so as to extend down to the lower surface of the flat surface of the light guide plate 300. Then, since the area of the PCB 400 is wide, heat transfer through the PCB 400 is better, and thus heat dissipation characteristics can be improved.

Thus, when mounting the high-output side emitting type LED package such as the present invention on the PCB 400, it is more advantageous because it does not require a separate aluminum chassis or bracket. In other words, top-view type LED packages have to be used for high power backlights such as TVs. In this case, the PCB on which the LED packages are mounted must be placed parallel to the incident surface of the light guide plate. This requires a separate aluminum chassis or bracket. However, when using the side-emitting type LED package according to an embodiment of the present invention as described above, the light emitting direction of the LED package is changed only by attaching the PCB 400 on which the LED packages are mounted to the main body 200. Since it is directed to the incident surface of the light guide plate 300, there is no need for a separate chassis or bracket.

On the other hand, in a preferred embodiment of the present invention by forming a thermal conductive layer 500 through a high viscosity thermal compound (Thermal Compound) having high thermal conductivity between the PCB 400 and the main body 200 can further improve the heat dissipation characteristics. have. The heat conduction layer 500 can eliminate the air layer between the main body 200 and the PCB 400, it is possible to make the heat transfer more smoothly. The thermal conductive layer 500 is preferably a thermal compound of 0.5 W / mK or more, preferably a natural curable silicone or resin material, thermosetting silicone material or resin material, non-hardening silicone material or resin material, or thermal conductivity Tapes and the like can be used. Even if the PCB 400 is not a metal PCB, the heat conductive layer 500 can smoothly transfer the heat to the main body 200 to increase the heat dissipation efficiency of the entire backlight unit.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

1 is a front view of a light emitting diode package according to an embodiment of the present invention;

2 is a bottom view of the LED package of FIG. 1;

3 is a cross-sectional view taken along line III-III of FIG. 1;

4 is a cross-sectional view taken along line IV-IV of FIG. 1;

5 is a cross-sectional view of a light emitting diode package according to another embodiment of the present invention;

6 is a schematic cross-sectional view of a backlight unit according to an embodiment of the present invention.

Claims (9)

A first pad having a first surface facing a first direction and a second surface facing a second direction opposite to the first direction; A second pad electrically separated from the first pad, the second pad having a third surface facing the first direction and a fourth surface facing the second direction; A first opening fixing the first pad and the second pad and having a support surface and exposing at least a portion of the first and third surfaces toward the first direction and the second surface toward the second direction, respectively; And a molding part having a second opening exposing at least a portion of the fourth surface. A light emitting diode chip seated on a first surface of the first pad and electrically connected to the first pad and the second pad and emitting light; A first lead electrically connected to the first pad and positioned outside the molding part; And And a second lead electrically connected to the second pad and separated from the first lead and positioned outside the molding part. The sum of the area of the lower surface of the first lead and the area of the lower surface of the second lead is 30% or more and 100% or less of the area of the support surface. The method of claim 1, And the first lead and the second lead extend perpendicular to first and third surfaces of the first pad and the second pad, respectively. The method of claim 1, At least one of the second surface of the first pad and the fourth surface of the second pad exposed through at least the second opening is a light emitting diode package. The method of claim 1, The light emitting diode package of claim 1, further comprising a reflective surface formed on the first surface on which the light emitting diode chip of the first pad is seated, the reflecting surface provided to surround the light emitting diode chip. main body; A light guide plate positioned on the main body; A PCB mounted on the main body; And And a light emitting diode package according to any one of claims 1 to 4 mounted on the PC and arranged to be aligned with a light incident part of the light guide plate. The method of claim 5, The PC unit is a backlight unit, characterized in that the metal PCB (metal PCB). The method of claim 5, And a heat conduction layer interposed between the body and the PC. The method of claim 5, And a light incident portion of the light guide plate is a side surface of the light guide plate, and the PC ratio extends between the light guide plate and the main body. The method of claim 5, And a first lead and a second lead of the light emitting diode package are bonded to the PC, and a line connecting the centers of the first and second openings is parallel to the surface of the PC.

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