LED packaging structure

An LED packaging structure has a substrate having two holes formed thereon. One of two conductive elements extends through the two holes to connect electrically to a conductive pad and a first electrode pad on the upper and lower surfaces of the substrate and the other of the two conductive elements extends through the holes to connect to the conductive strip and the second electrode pad on the upper and lower surfaces the substrate. A light-emitting chip electrically connects to the conductive pad and the conductive strip. The light-emitting chip is encapsulated by a protection colloid on the substrate, so as to make LED packaging structure easy to fabricate and avoid the short circuits of adjacent LED packaging structures due to contact between conductor materials therebetween.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention refers to a light-emitting diode (LED), and particularly to a packaging structure of an LED for improving fabricating yield and avoiding short circuit of adjacent LED packaging structures due to contact of their conductive elements.

2. Description of the Prior Art

Reference is made toFIG. 1, which is a prior art packaging structure of an LED as disclosed in U.S. Pat. No. Re. 36614, comprising a substrate10a, a light-emitting chip20a, a conducting wire30aand a protective unit40a(which is hereby incorporated by reference). The substrate10afurther comprises two conductor materials50arespectively disposed on the upper surface of the substrate10ato form a conductive pad51aand a conductive strip52aon the substrate10a, respectively, and further extending respectively along the opposite half-circle side walls of the substrate10ato the lower surface the substrate10ato form an electrode pad53athereon. One side of the light-emitting chip20ais electrically connected and secured to one of the conductive pad51a, and the conducting wire30ais used at both ends thereof to connected electrically and respectively to the other conductive strip52aand the other side of the light-emitting chip20a. Using the protection unit40a, the light-emitting chip20a, the conductive pad51a, the conductive strip52aand the conducting wire30aare encapsulated on the upper surface of the substrate10a.

In this case, the packaging structures of the LED are mass-manufactured by forming a plurality of LED packaging structures on a large-area substrate. To do this, a plurality of circle holes are formed on the large substrate, then the conductive pads, conductive strips and electrode pads are disposed on the upper and lower surfaces and the circle hole walls of the substrate by electroplating and etching; further, the light-emitting chips are disposed and electrically connected thereon, and then encapsulated by the protection unit on the substrate. Consequently, a plurality of interconnected LED packaging structures are formed. Finally the substrate is sliced along the direction of the aligned holes to separate the substrate into individual LED packaging structures with two opposite half-circle side walls. However, since the large-area substrate may be obliquely cut during the slicing process, this results in irregular half-circle side walls, thereby decreasing product yield.

Moreover, when a plurality of LED packaging structures are aligned in a matrix arrangement for use of display device, and two adjacent packaging structures are positioned close and thus may contact each other (as shown inFIG. 2), the half-circle side walls and the electrode pads of the adjacent LED packaging structures may be positioned close to and be in contact with each other, thereby resulting in a short-circuit. Therefore, two LED packaging structures need separated by a certain interval or a isolation element is disposed between two adjacent LED packaging structures, so as to avoid short-circuits of adjacent LED packaging structures. As a result, assembly and fabrication take longer and are more expensive, thereby leading to the degradation of the competitive power of the products.

Accordingly, this invention is provided to improve the above disadvantages with a reasonable design.

SUMMARY OF THE INVENTION

It is a first object of the present invention to provide an LED packaging structure, in which two holes are formed on a substrate thereof and two conductors extend respectively through the two holes to connect electrically to the conductive elements on the upper and lower surfaces of the substrate, whereby the LED packaging structure is easily fabricated.

It is a second object of the present invention to provide an LED packaging structure, in which the conductors extend through the holes of a substrate thereof and the conductive elements on the upper and lower surfaces of the substrate are separated from the edges of the substrate by a certain interval, thereby avoiding short-circuits of adjacent LED packaging structures due to contact therebetween.

According to the above-mentioned objects, the present invention provides an LED packaging structure, comprising the following elements. A substrate has upper and lower surfaces, and a conductive pad and conductive strip are disposed on the upper surface of the substrate, while a first electrode pad and a second electrode pad are disposed on the lower surface of the substrate. A light-emitting chip is arranged on the conductive pad and is electrically connected to the conductive pad and the conductive strip. A protection colloid encapsulates the light-emitting chip on the upper surface of the substrate.

The substrate has two holes through the upper and lower surfaces, two conductors extending respectively along the two holes such that one of the conductors is electrically connected at both of its terminals to the conductive pad and the first electrode pad, respectively, and the other conductor is electrically connected at both of its terminals to the conductive strip and the second electrode pad, respectively. Therefore, fabrication thereof is easy, and short-circuits of adjacent LED packaging structures due to contact of conductive elements thereof can be avoided.

DETAILED DESCRIPTION OF THE EMBODIMENTS

With reference toFIGS. 3 to 5, this invention is directed to an LED packaging structure10, in which two holes21are formed on a substrate20thereof, and two conductors22extends along the pair of holes21, respectively, such that one of the conductors22is connected to a conductive pad24on the upper surface23of the substrate20and a first electrode pad26on the lower surface25of the substrate20, and the other conductor22is connected to a conductive strip27on the upper surface23of the substrate20and a second electrode pad29on the lower surface25of the substrate20. Fabrication of the LED packaging structure10is thus easily performed and short-circuits between the adjacent LED packaging structures due to contact of conductive elements thereof can be avoided.

With reference toFIGS. 3 and 4, the substrate20has opposite upper and lower surfaces23and25, and two holes21are formed through the upper and lower surfaces23and25on the substrate20; the holes21are, for example, circular. Moreover, a conductive pad24and a conductive strip27are disposed on the upper surface23of the substrate20. First and second electrode pads26and29are disposed on the lower surface25of the substrate20at opposite ends, and two conductors22extend through the pair of the holes21, respectively, such that the conductors22are respectively connected at both terminals thereof to the conductive pad24on the upper surface23of the substrate20and the electrode pad26on the lower surface25of the substrate20, respectively. The conductors22are, for example, cylinders and affixed to the walls of the holes21of the substrate20. Additionally, the conductive pad24and the conductive strip27are separated by a certain interval from the edges of the adjacent substrate20, while the first and second electrode pads26and29are are separated by a certain interval, respectively, from the edges of the substrate20.

The light-emitting chip35is, for example, a light-emitting diode (LED), arranged on the conductive pad24. The light-emitting chip35has two electrodes36, one of which is electrically connected to the conductive pad24and the other of which is electrically to the conductive strip27via a electro-conducting wire40.

The protection colloid45is, for example, a transparent colloid, for encapsulating the light-emitting chip35, the conductive pad24and the conductive strip27on the upper surface23of the substrate20to form an LED packaging structure10.

With reference toFIG. 5, in the case that a plurality of LED packaging structures10is arranged in a matrix for forming a large-scale display panel50, the pair of the conductors22are arranged through the holes21and the upper surface23of the substrate20. The conductive pad24and the conductive strip27on the upper surface23of the substrate20are respectively separated from the edges of the adjacent substrate20by a certain interval, and the first and second electrode pads26and29on the lower surface25of the substrate20are respectively separated from the edges of the adjacent substrate20by a certain interval, so as to avoid short-circuits of adjacent LED packaging structures10due to contact between conductive elements thererof. Therefore, it is applicable for a plurality of LED packaging structures arranged in a matrix for forming a display panel50.

Therefore, the fabrication process is performed according to the following steps of fabricating LED packaging structures. A plurality of holes21are formed on a substrate10. The upper and lower surfaces23and25of the substrate20and the walls of the holes21are further plated with conductive materials by electroplating. Undesired portions are removed by etching to form the conductive pad24, the conductive strip27, the first and second electrode pads26and29, and the conductors22. A plurality of light-emitting chips35are disposed on the surface23of the substrate20and electrically connected to the conductive elements. The plurality of light-emitting chips35are encapsulated on the substrate20with a protection colloid45to form a plurality of interconnected LED packaging structures10. Finally, the substrate20is sliced along the gaps between adjacent conductive elements to form a plurality of separate LED packaging structures10, thereby increasing fabrication speed. Therefore, it is unnecessary to slice the walls of the holes across the holes, thus improving fabricating yield, speed and workability.

In conclusion, the LED packaging structure according to the invention is arranged to have two holes formed on a substrate and two conductors extending through the two holes respectively to connect electrically to the conductive elements on the upper and lower surfaces of the substrate. The structure is thus easy to fabricate. Moreover, the conductors extend through the holes of the substrate, and the conductive elements on the upper and lower surfaces of the substrate are separated from the edges of the substrate by a certain interval, so as to avoid short-circuits of adjacent LED packaging structures due to contact between conductive elements thereof. Fabrication processes and cost are thereby reduced.

Although possible embodiments of the invention have been described above, it is to be understood that the scope of the invention is not limited to these embodiments; in the same way, all equivalent structures and modifications as implemented in this specification and as illustrated in these drawings are covered within the scope of this invention, in order to protect the right of the inventor.