Lens and lamp using the same

A lens and a lamp using the same are provided. The lamp includes a lampshade, a base, a lens and a light emitting diode (LED). The lampshade and the lens are assembled on the base, wherein the lens is located in the lampshade. The lens has an accommodating portion, a first light exiting surface and a second light exiting surface. The first light exiting surface is located above the accommodating portion, and the second light exiting surface surrounds the first light exiting surface and located outside the accommodating portion. The first and second light exiting surfaces are concaves. The LED is disposed in the accommodating portion of the lens.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a lamp. Particularly, the invention relates to a lens and a lamp using the same.

2. Description of Related Art

In daily life, light emitting diodes (LEDs) have been widely used due to its advantages of small size and long service life.

It should be noticed that in a conventional LED application, since the LED is a directional light source, a light direct irradiating area located in front of the LED generally has high brightness, and light indirect irradiating areas have brightness lower than that of the light direct irradiating area. Due to the directionality of the LED, the LED is generally used in lamps requiring local high brightness, and when it is used in a decorative lighting lamp, problems of uneven brightness and relatively small viewing angle range are encountered.

SUMMARY OF THE INVENTION

The invention is directed to a lens with a simple shape, which is capable of improving a viewing angle range of a directional light source.

The invention is directed to a decorative lamp using a light emitting diode (LED) as a light source and having a relatively large viewing angle range.

The invention provides a lens, and a LED is adapted to be disposed in the lens. The lens has an accommodating portion, a first light exiting surface and a second light exiting surface. The first light exiting surface is located above the accommodating portion, and the second light exiting surface surrounds the first light exiting surface and located outside the accommodating portion. The first and second light exiting surfaces are concaves.

In an embodiment of the invention, the accommodating portion has a top light incident surface and a side light incident surface. The top light incident surface is located above the LED, and the side light incident surface surrounds the top light incident surface, and the LED is located in the side light incident surface.

In an embodiment of the invention, the first light exiting surface has a first sub light exiting surface and a second sub light exiting surface. The first sub light exiting surface is a plane and parallel to the top light incident surface, and the second sub light exiting surface surrounds the first sub light exiting surface and is connected to the second light exiting surface.

In an embodiment of the invention, the second sub light exiting surface is a slope or a curved surface.

In an embodiment of the invention, a cross-section of the first light exiting surface has a funnel shape.

In an embodiment of the invention, a diameter of the first sub light exiting surface is 0.5 mm.

In an embodiment of the invention, the second light exiting surface has a third sub light exiting surface and a fourth sub light exiting surface. The third sub light exiting surface is connected to the first light exiting surface, and the fourth sub light exiting surface is coaxial with the side light incident surface of the accommodating portion.

The invention provides a lamp including a lampshade, a base, a lens and a light emitting diode (LED). The base and the lampshade are assembled together, and the lens is disposed on the base and located in the lampshade. The lens has an accommodating portion, a first light exiting surface and a second light exiting surface. The first light exiting surface is located above the accommodating portion, and the second light exiting surface surrounds the first light exiting surface and is located outside the accommodating portion. The first and second light exiting surfaces are concaves. The LED is disposed in the accommodating portion of the lens.

In an embodiment of the invention, the accommodating portion has a top light incident surface and a side light incident surface. The top light incident surface is located above the LED, and the side light incident surface surrounds the top light incident surface, and the LED is located in the side light incident surface.

In an embodiment of the invention, the first light exiting surface has a first sub light exiting surface and a second sub light exiting surface. The first sub light exiting surface is a plane and parallel to the top light incident surface, and the second sub light exiting surface surrounds the first sub light exiting surface and is connected to the second light exiting surface.

In an embodiment of the invention, the second sub light exiting surface is a slope or a curved surface.

In an embodiment of the invention, a cross-section of the first light exiting surface has a funnel shape.

In an embodiment of the invention, a diameter of the first sub light exiting surface is 0.5 mm

In an embodiment of the invention, the second light exiting surface has a third sub light exiting surface and a fourth sub light exiting surface. The third sub light exiting surface is connected to the first light exiting surface, and the fourth sub light exiting surface is coaxial with the side light incident surface of the accommodating portion.

According to the above descriptions, the lens of the invention has a simple shape and a larger viewing angle range than convention, and the lens used in the lamp can change an optical path of the LED, so that the LED serving as the directional light source can also be applied in the decorative lamps.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

FIG. 1is a three-dimensional view of a lens according to an embodiment of the invention, andFIG. 2is a cross-sectional view of the lens along a section line A-A ofFIG. 1. Referring toFIG. 1andFIG. 2, the lens130has an accommodating portion132, a first light exiting surface134and a second light exiting surface136. The first light exiting surface134is located above the accommodating portion132, and the second light exiting surface136surrounds the first light exiting surface134and located outside the accommodating portion132. The first light exiting surface134and the second light exiting surface136are concaves. In detail, the accommodating portion132accommodates a light source, and a main function of the lens130of the present embodiment is to ameliorate an application range of a directional light source, so that the lens130is used for covering a light emitting diode.

The accommodating portion132of the lens130has a top light incident surface132aand a side light incident surface132b, where the top light incident surface132ais a plane, and the side light incident surface132bsurrounds the top light incident surface132a, and the top light incident surface132aand the side light incident surface132bcommonly form a space for accommodating the LED.

Moreover, the first light exiting surface134has a first sub light exiting surface134aand a second sub light exiting surface134b, wherein the first sub light exiting surface134ais a plane and is parallel to the top light incident surface132a, and the second sub light exiting surface134bsurrounds the first sub light exiting surface134aand is connected to the second light exiting surface136. In the present embodiment, the second sub light exiting surface134bis a slope. In other words, a cross-section of the first light exiting surface134has a funnel shape.

Moreover, the second light exiting surface136has a third sub light exiting surface136aand a fourth sub light exiting surface136b, wherein the third sub light exiting surface136ais connected between the first light exiting surface134and the fourth sub light exiting surface136b, and the fourth sub light exiting surface136bis coaxial with the side light incident surface132bof the accommodating portion132.

FIG. 3is a schematic diagram of a lamp using the lens ofFIG. 1, andFIG. 4is a schematic diagram of optical paths of light in the lens that is emitted from the LED. Referring toFIG. 3andFIG. 4, the lens130is applied in a lamp100, and the lamp100includes a lampshade110, a base120, the aforementioned lens130and a LED140. The base120and the lampshade110are assembled together, and the lens130is disposed on the base120and located in the lampshade110. The LED140is disposed in the accommodating portion132of the lens130, and a light emitting surface of the LED140faces to the top light incident surface132aof the accommodating portion132.

When the LED140emits light, the light enters the lens130through the top light incident surface132aand the side light incident surface132b, and since the LED140is a directional light source, most of the light enters the lens130through the top light incident surface132a.

A part of the light entering the lens130is projected to the third sub light exiting surface136aand the fourth sub light exiting surface136bof the second light exiting surface136, and a part of the light is projected to the first light exiting surface134, wherein the light projected to the first sub light exiting surface134adirectly emits out of the lens130due to an incident angle thereof, and the light projected to the second sub light exiting surface134bis reflected by the second sub light exiting surface134bdue to an incident angle thereof, and emits towards the third sub light exiting surface136a.

According toFIG. 4, it is known that if the first light exiting surface134is a plane, after the light emitted from the LED140is projected to the first light exiting surface134, it directly emits out of the lamp, so that a viewing angle range of the lamp100is concentrated in a light emitting direction of the LED140, which leads to a problem of uneven brightness due to that the light is concentrated to the front of the lamp100. By ameliorating the lens130, the first light exiting surface134has the planar first sub light exiting surface134aand the slant second sub light exiting surface134bthat forms an included angle with the first sub light exiting surface134a, wherein a diameter of the first sub light exiting surface134ais equal to or greater than 0.5 mm, so that the light emitted from the LED140can still emit out through the first sub light exiting surface134a(i.e. the light emitting direction). Moreover, the second sub light exiting surface134bcan further reflect the light projected thereon to the third sub light exiting surface136afor emitting, so as to improve the light viewing angle range of the lamp100.FIG. 5andFIG. 6are schematic diagrams of viewing angle ranges of the lamp ofFIG. 3, whereFIG. 5is a graphics obtained through software simulation, andFIG. 6is a graphics obtained through an actual measurement. According toFIG. 5andFIG. 6, it is known that the viewing angle range of the lamp100may reach about ±110 degrees. Taking 0 degree as the front of the lamp100, lighting of the lamp100can also be viewed by a user from the rear of the lamp100, which ameliorates a situation that the conventional directional light source can only be applied in lamps with fixed irradiation directions. By using the lens130of the present embodiment, a candle-style lamp can also use the LED as a light source. Moreover, the lamp100may have an even brightness.

In the aforementioned embodiment, although the second sub light exiting surface134bof a slope is taken as an example for descriptions, in other embodiments that are not illustrated, the second sub light exiting surface134bcan also be a curved surface such as a convex or a concave as long as partial penetration and partial reflection of the light is achieved to increase the light viewing angle range.

In the above descriptions, the “concave” refers to bend inwards the lens130, and the “convex” refers to bend outwards the lens130, and those skilled in the art should have known that the “concave” and the “convex” described in the aforementioned embodiment are relative concepts, and the invention is not limited to the text descriptions or figure expressions of the aforementioned embodiment.

In summary, the lens of the invention has a simple shape. Moreover, by using the lens in collaboration with the LED with directionality, the viewing angle range of the LED can be ameliorated, so that the LEI) can also be applied in decorative lamps, by which an application level of the LED is improved, and the lamp using the LED as a light source may have even brightness.