CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority of Chinese Application No. 201010215196.8, filed on Jun. 25, 2010.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lens, more particularly to a light-emitting diode lens.
2. Description of the Related Art
Light-emitting diodes (LEDs) are known to have advantages such as high efficiency, long service life, and low power consumption, and are gradually replacing conventional illuminating devices in various applications, such as display panels.
However, for applications that require shaped illumination fields (e.g., street illumination), correction of the illumination fields of the LEDs is required.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a LED lens that is capable of shaping illumination field of a LED light source into rectangular form.
The light-emitting diode (LED) lens of the present invention for covering a LED light source includes a lens body made of a transparent material. The lens body has one side formed with a light-exit surface which has a length along a longitudinal direction and which is configured along the longitudinal direction into a pair of convex surface areas and a concave surface area interconnecting the convex surface areas. The concave surface area has a minimum width along a first transverse direction smaller than a maximum width of each of the convex surface areas along the first transverse direction. The first transverse direction is transverse to the longitudinal direction. The lens body further has another side opposite to the light-exit surface. The concave surface area further has a minimum distance from the another side along a second transverse direction smaller than a maximum distance of each of the convex surface areas from the another side along the second transverse direction. The second transverse direction is transverse to the longitudinal direction and the first transverse direction.
The another side of the lens body is recessed to form a light-entrance portion adapted for receiving the LED light source. The light-entrance portion has a light-incident surface. The light-incident surface has a pair of end portions opposite to each other along the longitudinal direction and extending inclinedly away from the light-exit surface and away from each other. The light-entrance portion has a length along the longitudinal direction shorter than one-half of an overall length of the lens body along the longitudinal direction.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:
FIG. 1 is a perspective view of a preferred embodiment of the LED lens of the present invention;
FIG. 2 is a perspective view showing another side of the preferred embodiment;
FIG. 3 is a side elevation view of the preferred embodiment;
FIG. 4 is a top view of the preferred embodiment;
FIG. 5 is a view similar to FIG. 2 but further showing a LED light source received in a light-entrance portion;
FIG. 6 is a cross-sectional view along a longitudinal direction of the preferred embodiment with the LED light source received in the light-entrance portion;
FIG. 7 is a Candela distribution diagram of the preferred embodiment; and
FIG. 8 is a light shape diagram of the preferred embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 and FIG. 2, the preferable embodiment of the LED lens 1 of the present invention includes a lens body 10 made integrally of a transparent plastic material, such as by injection molding. The lens body 10 has one side (or top side) formed with a light-exit surface 11, and another side (or bottom side) opposite to the light-exit surface 11 and formed with a light-entrance portion 12 and at least one positioning protrusion 13 for positioning purposes.
Referring to FIG. 2 to FIG. 4, the light-exit surface 11 is a substantially gourd-shaped surface. More specifically, the light-exit surface 11 has a length along a longitudinal direction (i.e., x-axis direction) and is configured along the longitudinal direction into a pair of convex surface areas 113 and a concave surface area 114 interconnecting the convex surface areas 113. The convex surface areas 113 are substantially spherical surfaces, and the concave surface area 114 forms a restricted neck relative to the convex surface areas 113. Moreover, the concave surface area 114 has a length (A2) along the longitudinal direction shorter than a length (A1) of each of the convex surface areas 113 along the longitudinal direction. The concave surface area 114 further has a minimum width (W1) along a first transverse direction (i.e., Y-axis direction) smaller than a maximum width (W2) of each of the convex surface areas 113 along the first transverse direction. The first transverse direction is transverse to the longitudinal direction. The concave surface area 114 further has a minimum distance (L1) from the bottom side 101 along a second transverse direction (i.e., Z-axis direction) smaller than a maximum distance (L2) of each of the convex surface areas 113 from the bottom side 101 along the second transverse direction. The second transverse direction is transverse to the longitudinal direction and the first transverse direction. The light-exit surface 11 has a first axis of symmetry along the longitudinal direction and a second axis of symmetry along the first transverse direction.
Referring to FIG. 2 and FIG. 6, the bottom side 101 of the lens body 10 is recessed to form the light-entrance portion 12 that is in aligned with the concave surface area 114 along the second transverse direction. In this embodiment, the light-entrance portion 12 has a light-incident surface 121, and the light-incident surface 121 has a pair of end portions opposite to each other along the longitudinal direction and extending inclinedly away from the light-exit surface 11 and away from each other. Preferably, the light-incident surface 121 is a curved surface in a shape of a section of a wine barrel. In other words, referring to FIG. 6, the light-incident surface 121 has a curved cross-section along the longitudinal direction that opens away from the light-exit surface 11. The light-entrance portion 12 further has a surrounding surface 122 extending from a periphery of the light-incident surface 121 toward the bottom side 101 of the lens body 10. The surrounding surface 122 and the light-incident surface 121 cooperate to define a space 123 adapted for receiving a LED light source 103 (for example, a LED package or a light-emitting chip). Furthermore, the light-entrance portion 12 has a length (A4) along the longitudinal direction shorter than one-half of an overall length (A5) of the lens body 10 along the longitudinal direction.
Referring to FIG. 5 to FIG. 7, a large portion of light rays emitted from the light source 103 is refracted by the light-incident surface 121, enters the lens body 10, is refracted by the light-exit surface 11 and exits the light-exit surface 11 at a 60-degree angle relative to an optical axis of the LED lens 1. When the light rays pass through the light-incident surface 121, the light rays are refracted according to the curved design of the light-incident surface 121, toward the longitudinal direction in the lens body 10. Moreover, the light rays will not be overly concentrated on the concave surface area 114 since the concave surface area 114 forms a restricted neck relative to the convex surface areas 113. In this way, the light rays are distributed uniformly on the concave surface area 114 and the convex surface areas 113, and the illumination field is shaped into rectangular form as evident from the light shape diagram shown in FIG. 8.
In summary, the illumination field of the light source 103 can be shaped into rectangular form in view of the designs of the light-incident surface 121 and the light-exit surface 11 of the LED lens 1 of the present invention.
While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
Patent Grant
8382338
