Side view LED package and back light module comprising the same

Disclosed is a side view LED package that can be more accurately mounted onto a surface of a substrate such as a printed circuit board without distortion includes a first portion of a body allowing light to be emitted in front thereof, the first portion having a horizontal plane formed on a top or bottom side thereof; and a second portion of the body positioned backward with respect to a back end boundary line of the first portion, the second portion being formed with an inclined plane that is adjacent to the horizontal plane and has height decreased from the back end boundary line, wherein the inclined plane is partially formed with an added thickness portion that is flush with the horizontal plane.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean Patent Application No. 10-2008-0027732, filed on Mar. 26, 2008, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a side view light emitting diode (LED) package, and more particularly, to a side view LED package which can be more accurately mounted onto a surface of a substrate such as a printed circuit board (PCB) without being misaligned.

2. Discussion of the Background

Generally, a side view LED package is primarily used as a back light illumination device for displays and is configured to be aligned with a side surface of a light guide plate to allow light generated by the side view LED package to be projected into the light guide plate.

FIG. 1andFIG. 2illustrate a conventional side view LED package. Referring toFIG. 1andFIG. 2, a side view LED package30is placed adjacent to a side surface21of a light guide plate20. The side view LED package30includes a body that is divided into a front portion32and a rear portion34. An LED chip31for emitting light when electric power is applied thereto is embedded within the body.

The light generated from the LED chip31passes through a light-transmittable encapsulant, which is partially provided in the front portion32of the body, and is then emitted through a front face of the front portion32. Since the front face of the front portion32faces the side surface21of the light guide plate20, the side view LED package30projects light into the light guide plate20.

For ease of manufacture, the body of a conventional side view LED package30including a front portion32and rear portion34that is molded within a mold (not shown), may be shaped such that the rear portion34is narrower than the front portion32. This configuration allows the body of the side view LED package30to be easily separated from the mold and results in bottom and top sides of the front portion32of the body being respectively formed with horizontal planes, while bottom and top sides of the rear portion34of the body are respectively formed with inclined planes having height differences with respect to a horizontal plane of the front portion32.

When the side view LED package30constructed with this configuration is mounted onto a PCB10by a surface mounting technique (SMT), the height difference between the bottom surface of the front portion32and the bottom surface of the rear portion34, can cause the side view LED package30to be skewed or misaligned when mounted onto the PCB10, as shown inFIG. 2. Further, conventional surface mounting techniques require a vacuum picker2to attach to a top surface of the side view LED package30and then transfer the side view LED package30to a desired position. In this transfer method the height difference between the top surface of the front portion32and the top surface of the rear portion34can prevent the vacuum picker from attaching to, and transferring the side view LED package30in a level, horizontal position, which can lead to misalignment when the side view LED package30is surface mounted on the PCB10as shown inFIG. 1andFIG. 2.

If the side view LED package30is misaligned when mounted onto the PCB, the front light emitting surface of the side view LED package30cannot be properly aligned with the side surface of the light guide plate20, thereby causing the light emitting efficiency of the side view LED package30to be reduced.

SUMMARY OF THE INVENTION

The present invention provides a side view LED package, that can be more accurately surface mounted onto a PCB or the like by providing thickened portions on the rear portion of the body of the side view LED package to compensate for the height differences between the front portion of the body of the side view LED package and the rear portion of the body of the side view LED package.

The present invention discloses a side view LED package, which comprises a first portion of a body allowing light to be emitted in front thereof, the first portion having a horizontal plane formed on a top or bottom side thereof; and a second portion of the body positioned backward with respect to a back end boundary line of the first portion, the second portion being formed with an inclined plane that is adjacent to the horizontal plane and has height decreased from the back end boundary line, wherein the inclined plane is partially formed with a thickened portion that is flush with the horizontal plane.

The present invention also discloses a back light module comprising a light guide plate, a PCB, and a side view LED package. Here, the side view LED package includes a first portion of a body allowing light to be emitted in front thereof toward the light guide plate, the first portion having a horizontal plane formed on a top or bottom side thereof; and a second portion of the body positioned backward with respect to a back end boundary line of the first portion and formed with inclined plane from the back end boundary line, wherein a thickened portion is partially formed on the inclined plane and flush with the horizontal plane, wherein the thickened portion and the horizontal plane are closely contacted with the PCB.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

FIG. 3is a side view illustrating a side view LED package and a back light module according to one embodiment of the present invention.

As depicted inFIG. 3, the back light module comprises a PCB100, a light guide plate200and a side view LED package300. The side view LED package300is located adjacent to a side surface201of the light guide plate200. The side view LED package300includes a body301which includes a front portion320and a rear portion340. An LED chip310for emitting light when electric power is applied thereto is embedded within the body301. Although not shown, the application of electric power to the LED chip310is performed through lead frames extending from the interior of the body to the exterior thereof.

To permit light generated from the LED chip310to be emitted from the body301that is opaque, the body301includes a light-transmittable encapsulant302. Since the encapsulant302is extended up to a front face of the front portion320of the body301, the side view LED package300can emit light outwardly from the front portion320of the body301.

The body301may be formed by a plastic molding process using a mold (not shown). To permit a body301molded within a mold to be more easily separated or released from the mold, the mold is shaped to have a wider front portion and a narrower rear portion. As such, although bottom and top sides of the front portion320of the body may be respectively formed with horizontal planes322and324, bottom and top sides of the rear portion340of the body are respectively formed with inclined planes342and344which have height differences with respect to the horizontal planes322and324of the front portion320.

As a result of these height differences, and with reference toFIG. 4, a back end boundary line B is formed between the front and rear portions320and340of the body, i.e., on a back end of the front portion320. Here, the rear portion340is positioned to the rear of the back end boundary line B, and the bottom inclined plane342of the rear portion340is configured such that its height is gradually decreased as the distance along the bottom inclined plane342from the back end boundary line B is increased. Similarly, the top inclined plane344of the rear portion340is configured such that its height is gradually decreased as the distance along the top inclined plane344from the back end boundary line B is increased.

At a bottom side of the body301, the height difference between the bottom horizontal plane322and the bottom inclined plane342may cause the side view LED package300to be misaligned when mounted onto the PCB100as previously described with respect to conventional devices as depicted inFIG. 1andFIG. 2. To reduce the risk of this condition, the side view LED package300according to this embodiment further includes a bottom thickened portion327that compensates for the height differences caused by the inclination of the bottom inclined plane342. As shown by the hatched portion inFIG. 3, the bottom thickened portion327on the bottom of body301may be arranged on a portion of the bottom inclined plane342and is flush with the bottom horizontal plane322. In the plastic molding process of the body301, the bottom thickened portion327can be formed such that it extends from the back end boundary line B to a region of the bottom inclined plane342.

Accordingly, the bottom horizontal plane322and the bottom thickened portion327formed on the bottom inclined plane342are in surface to surface contact with a surface of the PCB100, so that the side view LED package300can be mounted on the PCB100with a reduced risk of being misaligned.

Further, a top side of the body301may also be formed with a top thickened portion347to compensate for the height difference between the top horizontal plane324and the top inclined plane344. As shown by the hatched portion inFIG. 3, the top thickened portion347may be arranged on a portion of the top inclined plane344of the body301and is flush with the top horizontal plane324of the body301. In one embodiment, in the plastic molding process of the body301, the top added thickness portion347may be formed such that it extends from the back end boundary line B to a region of the top inclined plane344.

Since the top thickened portion347provides a relatively wide horizontal surface, to which a vacuum picker2can attach, the side view LED package300can be more accurately mounted onto the PCB100since the side view LED package300can be picked up in a level, horizontal position by the vacuum picker2. Accordingly, the top thickened portion347also allows the side view LED package300to be mounted to the PCB10with a reduced risk of misalignment.

The bottom and top thickened portions327and347may be molded as an integral part of the body301of the side view LED package300, or alternatively the body301may be formed first and then the bottom and top thickened portions327and347may be formed as additional members which are subsequently attached to the body301.

FIG. 4is a plan view illustrating a side view LED package300according to this embodiment. As depicted therein, the top thickened portion347is disposed on a portion of the top inclined plane344of the body301. Further, although not shown inFIG. 4, the bottom thickened portion327(seeFIG. 3) of an approximately similar shape to the top thickened portion347may be disposed on a portion of the bottom inclined portion of the body301. When disposed in this manner, the top thickened portion347and the bottom thickened portion327extend rearward from the back end boundary line B of the front portion320of the body301to partial regions of the inclined planes342and344, respectively.

Thus, differences in height between the front portion320and rear portion340of body301are accommodated by the addition of the top thickened portion347and the bottom thickened portion327. The addition of the top thickened portion enhances the mounting process by permitting a vacuum picker2to attach to the body301and transfer the body301to its mounting location in a more level, horizontal orientation. The addition of the bottom thickened portion347permits the mounting of the side view LED package300with a reduced risk of misalignment. By improving the mounting process in this fashion the side view LED package300can be more accurately placed with respect to the light guide plate200with a reduced risk of misalignment. Accurate placement thereby improves the amount of light that can be projected into the light guide plate200and contributes to enhancing the light efficiency of a back light module comprising a side view LED package in accordance with the exemplary embodiments of the present invention.