Patent Application
20090166656
1. Field of the Invention
The present invention relates to a light emitting diode, and particularly to a light emitting diode, which can be directly used in a lighting equipment without secondary optics.
2. Description of related art
Light emitting diodes (LEDS) are a commonly used light source in applications including lighting, signaling, signage and displays. The LED has several advantages over incandescent and fluorescent lamps, including high efficacy, high brightness, long life, and stable light output. It creates much higher illuminance and space brightness with less electricity consumption.
A related LED is shown in
When the related LED is used in a lighting equipment, particularly a road lamp, secondary optics 17 have to be added to redirect the light to meet the specific lighting requirements of the road lamp. These optics 17 are called “secondary” to distinguish them from the “primary optics” of the conventional LED itself, such as the encapsulation 15. The design of the secondary optics 17 is called “the secondary optics design. In general, the secondary optics 17 includes lenses, which are usually positioned between the related LED and the desired direction of the light emission.
However, the secondary optics 17 is separately manufactured from the primary optics, i.e. the encapsulation 15 and then assembled together with the primary optics, which leads to a raise of the cost of the lighting equipment. As the lighting industry is a highly price competitive market, device manufacturers are motivated to reduce the bill of materials of a given device, enabling either higher profit or a reduced price to the end user.
What is needed, therefore, is an LED, which has an integral secondary optics and can be directly used in a lighting equipment without a separate secondary optics to meet the specific lighting requirements of the lighting equipment, particularly a road lamp.
In accordance with an embodiment of the present invention, a light emitting diode (LED) comprises a base, a chip body and an encapsulation portion sealing the chip body in the base. The base has a concave depression defined therein. The depression has a bottom wall and a sidewall expending upwardly from the bottom wall. The sidewall is arranged in a half-ellipsoidal surface round the bottom wall. The chip body is disposed on the bottom wall. The encapsulation portion has a bottom portion and a top portion formed on the bottom portion. The bottom portion has an outer surface mating with the depression, and the top portion has a convex, half-ellipsoidal surface. Light generated by the chip body has a portion directly emitting through the convex, half-ellipsoidal surface and anther portion reflected by the sidewall to run through the convex, half-ellipsoidal surface. The light is re-directed by convex, half-ellipsoidal surface to radiate out of the LED.
Other advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:
Many aspects of the present LED can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present apparatus. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
The base 200 has a rectangular parallelepiped configuration, and has a concave depression 220 defined therein. The depression 220 has a flat bottom wall 222 and a sidewall 224 slantwise expending upwardly from the bottom wall 222. The sidewall 224 is arranged in a half-ellipsoidal surface round the bottom wall 222. In other words, the depression 220 defined by the sidewall 224 and the bottom wall 22 together has an inverted frustum-shaped configuration. Furthermore, the bottom wall 222 and a horizontal cross-section of the depression 220 parallel to the bottom wall 222 each have an elliptic shape. The elliptic cross-section of the depression 220 has a size gradually increasing along a direction from the bottom wall 222 towards a top side of the base 200.
The chip body 300 is mounted on the bottom wall 222 of the depression 220 via a silver paste or other conventional method. The chip body 300 can electrically connect to a printed circuit board via conventional methods.
The base 200 is made of metal material such as aluminum; the inner surface of the sidewall 224 is polished so that the sidewall 224 serves as a light reflector to efficiently reflect the light from the chip body 300. However, in another embodiment as shown in
The encapsulation portion 400 serves to redirect the light from the chip body 300 and the light reflector, in addition to protecting the chip body 300 from external physical and/or electrical shock. The encapsulation portion 400 has a shape of an ellipsoid, and can be divided into a top portion 420 and a bottom portion 440.
The bottom portion 440 is located within the depression 220. The bottom portion 440 has an outer surface 442 mates with the inner surface of the depression 220 so that the chip body 300 is sealed in the depression 220 by the encapsulation portion 400.
The top portion 420 is formed on the top side of the bottom portion 440, and is in shape of a half-ellipsoid. The top portion 420 has a convex, half-ellipsoidal surface 422 to control of the direction of the light radiated from the chip body 300 and the light reflector and emitted out of the LED 100.
By the presence of the sidewall 224 of the depression 220 and the convex, half-ellipsoidal surface 422 of the encapsulation portion 400, the light from the chip body 300 can be reflected and redirected to meet the specific lighting requirements of the road lamp, without the necessity of a separate secondary optics assembled over the LED. Furthermore, the LED 100 of the instant invention without the separate secondary optics can achieve the same illuminance and space brightness as the related LED with the separate secondary optics. Therefore, the cost of a lighting equipment with the LED 100 is decreased due to the omission of the separate secondary optics. In addition, the lighting equipment with the LED 100 can have a compact design.
In the embodiment shown in
It is believed that the present invention and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200710186117.3 | Dec 2007 | CN | national |
