1. Field of the Invention
The present invention generally relates to a light source and, in particular, to a light-emitting diode (LED) package.
2. Description of Related Art
As the luminous efficiency of light emitting diodes (LEDs) is increasingly improved, LEDs have replaced fluorescent lamps and incandescent lamps in some fields, for example, lamps of scanners requiring for quick response, lamps of projection apparatus, backlight sources or front light sources of liquid crystal displays (LCDs), illumination for dashboards of automobiles, traffic lights, common illumination devices, etc. Compared with conventional lamps, the LEDs have absolute advantages, for example, small volume, long lifespan, low driving voltage/current, non-fragile, mercury free (no pollution), and good luminous efficiency (power saving).
FIG. 1 is a schematic structural view of a conventional LED package. Referring to FIG. 1, the conventional LED package 100 includes an LED chip 110, a lead frame 120, and an encapsulant 130. The LED chip 110 is disposed on the lead frame 120 and electrically connected therewith. The encapsulant 130 wraps the LED chip 110 and a part of the lead frame 120 for protecting the LED chip 110. The encapsulant 130 has a convex top surface 132 for preventing the total internal reflection (TIR) of the beam 112 emitted from the LED chip 110 due to the interface between the encapsulant 130 and air.
FIG. 2 is a schematic structural view of another conventional LED package. Referring to FIG. 2, the other conventional LED package 200 includes an LED chip 210, a circuit board 220, and an encapsulant 230. The LED chip 210 is disposed on the circuit board 220 and electrically connected therewith. The encapsulant 230 is disposed on the circuit board 220 and wraps the LED chip 210. The encapsulant 230 also has a convex top surface for preventing the TIR of the beam 212 emitted from the LED chip 210.
However, referring to FIGS. 1 and 2, the range of the light emitting angle θ1 and θ2 of the conventional LED packages 100 and 200 is large, approximate to 180 degrees, such that the LED packages 100 and 200 are not suitable for illuminating distant objects. For example, when the LED package 100 or 200 is applied as a light source in the projection apparatus (not shown), the beam 112 or 212 is hard to be mostly converged on the light valve (not shown) of the projection apparatus, such that the brightness of the light valve is not enough.