Light emitting device

Abstract

A light emitting device is proposed, which emits light while connected to the power. The light emitting device includes a light emitting element having at least two electrodes disposed at the side of the light output surface thereof; and a base member having a recess and lead portions corresponding to the electrodes, the light emitting element being mounted on the base member and received in the recess, wherein the light output surface faces toward opening of the recess that becomes smaller while approaching the light output surface, and the electrodes are respectively in electrical connection with the lead portions that extend from the connection positions to outer edge of the base member for power connection. The light emitting device of the present invention has advantages of short current path, low series thermal resistance and low cost. In addition, the depth of the recess can further be increased to improve light collecting efficiency.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to light emitting devices and, more particularly, to a light emitting device that can be applied to high power light emitting diodes. [0003] 2. Description of Related Art [0004] Currently, light emitting diodes (LEDs) that are characterized by long lifetime, small volume, low heat dissipation, low power consumption, fast response speed and single color light emission are widely used in indicator lights, bill boards, traffic lights, auto lamps, display panels, communication tools, consumer electronics and so on. Accordingly, different packaging techniques are developed for LEDs packaging, which results in different package structures of LEDs. [0005] FIGS. 1(A) to 1(C) show a flip chip packaging process. As shown in FIG. 1(A), a plurality of conductive bumps 11 is formed on an aluminum substrate 10. Then, as shown in FIG. 1(B), an LED chip 12 is attached to the aluminum substrate 10 upsid...

AI Technical Summary

Benefits of technology

[0013] Another objective of the present invention is to provide a light emitting device which can reduce the series thermal resistance.

[0014] A further objective of the present invention is to provide a light emitting device which can reduce the fabrication cost.

[0015] Still another objective of the present invention is to provide a light emitting device which can improve the light collecting efficiency.

[0017] Compared with the prior art, the light emitting device of the present invention achieves a much simpler light emitting device of thin thickness by combining a light emitting element with a base member which is connected to the power through lead portions of the base member, thereby resulting in short current path and low series thermal resistance and low cost. In addition, the depth of the recess can be increased to improve the light collecting efficiency.

Problems solved by technology

In addition, since the LED chip is electrically connected to the outside through the aluminum or ceramic substrate, the conductive path is very long, which results in too much heat absorption by the aluminum or ceramic substrate, thereby making the mass production difficult.

Furthermore, if several chip products are applied to the aluminum or ceramic substrate, the aluminum or ceramic substrate becomes so weak that it needs to be processed before the reflow process, thereby resulting in high fabrication cost.

In the above two packaging processes, high series thermal resistance leads to low reliability.

Further, since the stack technique is used in the above two packaging processes, the packaged products become very thick.

However, such a shallow recess will affect light collecting efficiency.

Thus, high cost of the ceramic substrate and addition of the aluminum substrate result in high fabrication cost.

Accordingly, the light emitting device can not be used in high power LED package.

4(A) to 4(C), there also exists the problem of bad light collecting efficiency.

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