Patent Application
20120106165
1. Technical Field
The present disclosure relates to LED (light emitting diode) units, and more particularly, to an LED unit having a lens.
2. Description of Related Art
Light emitting diodes (“LEDs”) are widely used as new types of light sources in various applications such as road lamps, traffic lamps, tunnel lamps, resident lamps and so on. A lens is often used with an LED for collimating the light beams generated from the LED in a predetermined pattern. In LED products designed to illuminate areas at a long distance, a convex lens may be used to converge the light beams emitted from the LED. However, in other applications, such as vehicle headlamps, the LED products need to be able to provide illuminations not only to the area far away from the LED, but also the area near the LED. LED products with the conventional convex lens may not meet such requirements.
What is needed, therefore, is an LED unit which can overcome the deficiencies as described above.
Many aspects of the present disclosure 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 disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
In one embodiment, the LED 10 generates white light. However, other types of LEDs which generate different light colors may also be used in the LED unit 100. The lens 20 may be made of transparent materials such as epoxy, silicon, glass and so on. Referring to
The first member 22 includes a convex part 222 and a sawtooth part 221 formed on the convex part 222. The convex part 222 curves outward from the top face 250 of the base 25. Circumferences of the convex part 222 have diameters gradually decreasing outward from the top face 250 to form a dome. The convex part 222 may converge incident light into narrow light beams to illuminate areas far away from the LED unit 100. Preferably, the convex part 222 has an optical axis O perpendicular to the light incident face 21 of the base 25. The LED 10 may be placed on the axis O and on the concave side of the lens 20 so that the light emitted by the LED 10 may be collimated by the convex part 222 to parallel light beams emitted out of the LED unit 100. The sawtooth part 221 may be formed on a top of the convex part 222. The sawtooth portion 221 may include a plurality of teeth 223 oriented upwardly. The sawtooth portion 221 may function as a first light emergent face 27 to diffuse the light beams from the light incident face 21 so that a wider area far away from the LED unit 100 may be illuminated. The convex portion 222 is intersected by a plane 24, which is connected to the second member 26. The plane 24 is bordered by a curved top edge 240 and a straight bottom edge 242. The plane 24 is at an angle α from the light incident face 21, wherein the angle α may be equal to or less than 90 degrees. The plane 24 may reflect some of the incident light towards the sawtooth part 221. As a result, a light-utilization efficiency of the lens 20 may be increased. A reflecting surface, which faces the lens 20, of the plane 24 may be formed by natural total reflection or coated with a high reflective material.
The second member 26 is connected with the first member 22. A continuous annular lateral face 28 comprises a sidewall of the first member 22 and a sidewall of the second member 26. The continuous annular lateral face 28 is connected to the top face 250 of the base 25. The continuous annular lateral face 28 has a largest height where the second member 26 and the first member 22 join. The second member 26 has an inclined top face intersects with the plane 24 at the straight bottom edge 242. The inclined top face of the second member 26 may function as a second light emergent face 23 to direct light from the LED 10 to illuminate areas near the LED unit 100. The second light emergent face 23 is at an angle β from the light incident face 21, wherein the angle β is smaller than the angle α. An angle γ between the second light emergent face 23 and the plane 24, measured facing the LED 10, is larger than 180 degrees.
When the LED unit 100 is applied to a headlamp of a vehicle, light emitted from the first light emergent face 27 may form a high beam to illuminate areas far away from the vehicle; whereas light emitted from the second light emergent face 23 may form a low beam to illuminate areas near the vehicle. As a result, areas in front of the vehicle may have a better visibility.
It is believed that the present disclosure 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 present disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 099137734 | Nov 2010 | TW | national |
