Patent Publication Number: US-2012044698-A1

Title: Lens and lamp using the same

Description:
This application claims the priority benefit of U.S. Provisional Application Ser. No. 61/375,860, filed on Aug. 22, 2010. This application also claims the priority benefit of a Taiwan application serial no. 99142398, filed on Dec. 6, 2010. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a lamp. More particularly, the invention relates to a lens and a lamp using the lens. 
     2. Description of Related Art 
     Light emitting diode (LED) light sources have advantages of small volume occupancy and long life time, and therefore it is more common to apply the LED light sources in our daily lives. 
     It should be mentioned that the conventional LED light sources are directional. Therefore, the direct lightening region located in front of an LED light source has greater luminance than that of the indirect lightening region. The directional LED light sources are often applied to lamps characterized by great luminance instead of being applied to decorative lamps. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a lens with a simple look and low cost barrier. 
     The invention is further directed to a decorative lamp in which an LED serves as a light source. 
     The invention provides a lens. The lens has a curved light incident surface, a first light incident surface, a first light emitting surface, and a second light emitting surface. The first light incident surface surrounds the curved light incident surface, and the curved light incident surface and the first light incident surface together constitute an accommodation space. The first light emitting surface is located above the curved light incident surface. The second light emitting surface is located at an outer side of the lens and corresponds to the first light incident surface located at an inner side of the lens. Besides, the second light emitting surface surrounds the first light emitting surface. 
     The invention further provides a lamp that includes a lampshade, a base assembled to the lampshade, the aforesaid lens, and an LED light source. The lens is configured on the base and located in the lampshade. The LED light source is configured within the accommodation space of the lens. 
     According to an embodiment of the invention, the curved light incident surface is a curved concave. 
     According to an embodiment of the invention, the lens or the lamp using the lens further has an auxiliary surface that surrounds the first light incident surface. The auxiliary surface surrounds a circumference of the first light incident surface, and a diameter of the auxiliary surface is an outer diameter of the first light incident surface. 
     According to an embodiment of the invention, the first light incident surface is a plane, an inclined surface, or a curved surface. 
     According to an embodiment of the invention, the auxiliary surface is a circumferential surface of the first light incident surface. 
     According to an embodiment of the invention, the second light emitting surface has a first portion and a second portion, an inner diameter of the second portion is equal to an outer diameter of the first portion, and an outer diameter of the second portion is greater than the inner diameter of the second portion. The first portion of the second light emitting surface is an inclined surface or a curved concave. The second portion of the second light emitting surface is an inclined surface or a curved surface. 
     According to an embodiment of the invention, the lamp further includes a light source lens configured on the LED light source. 
     Based on the above, the lens of the invention has the simple look and low cost barrier. When the lens of the invention is used in the lamp, the light path of the LED light source can be adjusted, such that the LED light source is also applicable to the decorative lamp. 
     In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanying figures are described in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  and  FIG. 2  are schematic views illustrating a lens at different viewing angles according to an embodiment of the invention. 
         FIG. 3  is a schematic cross-sectional view taken along a sectional line A-A′ in the lens depicted in  FIG. 1 . 
         FIG. 4  is a schematic view illustrating a lamp that uses the lens depicted in  FIG. 1 . 
         FIG. 5  illustrates light traces of the lens when the LED light source of the lamp depicted in  FIG. 4  emits light. 
         FIG. 6  is a polar radiation view illustrating the beam shape when the lens depicted in  FIG. 4  is made of polycarbonate (PC). 
         FIG. 7  is a cross-sectional view illustrating the beam shape when the lens is made of PC. 
         FIG. 8  is a polar radiation view illustrating the beam shape when the lamp has the lens that is made of polymethyl methacrylate (PMMA). 
         FIG. 9  is cross-sectional view illustrating the beam shape when the lamp has the lens that is made of PMMA. 
         FIG. 10  is a schematic view illustrating the LED light source on which a light source lens is further configured. 
         FIG. 11  is a cross-sectional view illustrating a lens according to a second embodiment of the invention. 
         FIG. 12  is a schematic view illustrating light traces of the LED light source and the lens depicted in  FIG. 11 . 
         FIG. 13  is a polar radiation view illustrating the beam shape when the lens depicted in  FIG. 11  is made of PC. 
         FIG. 14  is a cross-sectional view illustrating the beam shape when the lens depicted in  FIG. 11  is made of PC. 
         FIG. 15  is a polar radiation view illustrating the beam shape when the lamp has the lens that is made of PMMA. 
         FIG. 16  is cross-sectional view illustrating the beam shape when the lamp has the lens that is made of PMMA. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment  
       FIG. 1  and  FIG. 2  are schematic views illustrating a lens at different viewing angles according to an embodiment of the invention.  FIG. 3  is a schematic cross-sectional view taken along a sectional line A-A′ in the lens depicted in  FIG. 1 . With reference to  FIG. 1 ,  FIG. 2 , and  FIG. 3 , the lens  100  of this embodiment has a curved light incident surface  102 , a first light incident surface  104 , a first light emitting surface  108 , and a second light emitting surface  110 . The first light incident surface  104  surrounds the curved light incident surface  102 , and the curved light incident surface  102  and the first light incident surface  104  together constitute an accommodation space S. The first light emitting surface  108  is located above the curved light incident surface  102 . The second light emitting surface  110  is located at an outer side of the lens  100  and corresponds to the first light incident surface  104  located at an inner side of the lens  100 . Besides, the second light emitting surface  110  surrounds the first light emitting surface  108 . 
     As shown in the cross-sectional view of  FIG. 3 , the curved light incident surface  102  is a curved concave in the lens  100 , and the first light incident surface  104  is a plane. The lens  100  further has an auxiliary surface  106  that surrounds the first light incident surface  104 . The auxiliary surface  106  surrounds a circumference of the first light incident surface  104 . A diameter W 1  of the curved light incident surface  102  is an inner diameter of the first light incident surface  104 , and a diameter W 2  of the auxiliary surface  106  is an outer diameter of the first light incident surface  104 . The outer diameter W 2  is greater than the inner diameter W 1 . 
     The second light emitting surface  110  has a first portion  112  and a second portion  114 , and an inner diameter W 3  of the second portion  114  is equal to an outer diameter of the first portion  112 . As shown in the cross-sectional view of  FIG. 3 , the first portion  112  of the second light incident surface  110  is a curved concave in the lens  100 , and the second portion  114  is an inclined plane according to this embodiment. 
       FIG. 4  is a schematic view illustrating a lamp that uses the lens depicted in  FIG. 1 . With reference to  FIG. 2 ,  FIG. 3 , and  FIG. 4 , the lens  100  is applied to a decorative lamp  200 . The lamp  200  includes a lampshade  210 , a base  220 , the aforesaid lens  100 , and an LED light source  230 . The base  220  is assembled to the lampshade  210 . The lampshade  210  can be in any shape, which is determined based on the requirements of the decorative lamp  200 . The lens  100  is configured on the base  220  and located in the lampshade  210 . The LED light source  230  is placed into the accommodation space S of the lens  100  through an opening formed by the auxiliary surface  106 . 
       FIG. 5  illustrates light traces of the lens when the LED light source of the lamp depicted in  FIG. 4  emits light. With reference to  FIG. 5 , when the LED light source  230  emits light, the light enters the lens  100  from the curved light incident surface  102 . The radian of the curved light incident surface  102  is conducive to light refraction, such that the viewing angle of the lamp  200  can be enlarged when the light emitted by directional LED light source  230  is refracted by the curved light incident surface  102 . The light refracted by the curved light incident surface  102  is further refracted by the second light incident surface  110  and then emitted out of the lens  100 . Note that a portion of the light is refracted to the first portion  112  of the second light emitting surface  110  close to the first light emitting surface  108 . The portion of the light is then completely reflected and emitted out from the first light emitting surface  108 . Thereby, the light with uniform luminance can be emitted from the top of the lens  100 . 
       FIG. 6  is a polar radiation view illustrating the beam shape when the lamp depicted in  FIG. 4  is applied.  FIG. 7  is a cross-sectional view illustrating the beam shape when the lamp is applied. It can be observed from  FIG. 6  and  FIG. 7  that the viewing angle of the lamp  200  ranges from about 85 degrees to about −85 degrees. Namely, the range of the viewing angle of the lamp  200  is about 170 degrees in total. Within the range of the viewing angle of the lamp  200 , the light is concentrated in the front, and the luminance is uniform. 
     Note that the beam shape is subject to the material of the lens  100  in the lamp  200 . In  FIG. 6  and  FIG. 7 , the lens  100  is made of PC.  FIG. 8  is a polar radiation view illustrating the beam shape when the lamp has the lens that is made of PMMA.  FIG. 9  is cross-sectional view illustrating the beam shape when the lamp has the lens that is made of PMMA. In comparison with  FIG. 6 ,  FIG. 7  and  FIG. 8 ,  FIG. 9 , the difference in the material of the lens poses an impact on the beam shape and uniformity of luminance. In view of the above, the material of the lens can be determined based on actual requirements in order to obtain the desirable beam shape and achieve favorable uniformity of luminance. 
       FIG. 10  is a schematic view illustrating the LED light source on which a light source lens is configured. With reference to  FIG. 4  and  FIG. 10 , the lamp  200  can further include a light source lens  240  configured on the LED light source  230  and located between the LED light source  230  and the lens  100 . The light source lens  240  in the lamp  200  can optimize the beam shape and uniformize the luminance. 
     Second Embodiment  
     This embodiment is similar to the first embodiment. The difference therebetween lies in that the shape of the lens is slightly modified in this embodiment, and the decorative lamp of this embodiment can still have the wide viewing angle, favorable beam shape, and uniform luminance in comparison with the conventional decorative lamp. 
       FIG. 11  is a cross-sectional view illustrating a lens according to a second embodiment of the invention.  FIG. 12  is a schematic view illustrating light traces of the LED light source and the lens depicted in  FIG. 11 . Please refer to  FIG. 11  and  FIG. 12 . It is shown in the cross-sectional view of  FIG. 11  that the first light incident surface  304  of the lens  300  of this embodiment is an inclined surface, which is different from that of the first embodiment. Besides, the diameter of the auxiliary surface  306  is the outer diameter W 4  of the first light incident surface  304 , and the auxiliary surface  306  is a circumferential surface of the first light incident surface  304 . 
     The diameter W 5  of the second portion  314  of the second light emitting surface  310  is equal to the outer diameter of the first portion  312 . As shown in the cross-sectional view of  FIG. 11 , the first portion  312  is a curved concave, and the second portion  314  is a plane. 
     It can be learned from  FIG. 12  that the light emitted from the LED light source  230  enters the lens  300  through the curved light incident surface  102  and the first light incident surface  304 . After the light is refracted by the curved light incident surface  102  and the first light incident surface  304 , the light is refracted by the second light emitting surface  310  and then emitted out of the lens  300 . Additionally, the light that is refracted by the curved light incident surface  102  to the first portion  312  of the second light emitting surface  310  close to the first light emitting surface  308  is completely reflected and then emitted from the first light emitting surface  308 . 
       FIG. 13  is a polar radiation view illustrating the beam shape when a lamp having the lens depicted in  FIG. 11  is applied.  FIG. 14  is a cross-sectional view illustrating the beam shape when a lamp having the lens depicted in  FIG. 11  is applied. With reference to  FIG. 13  and  FIG. 14 , the material of the lens  300  as shown in  FIG. 13  and  FIG. 14  is the same as the material of the lens as shown in  FIG. 6  and  FIG. 7 , i.e., the lens  300  depicted in  FIG. 13  and  FIG. 14  is made of PC as well. In comparison with the lamp described in the first embodiment, the lamp having the lens  300  of this embodiment has relatively uniform luminance within the range of the viewing angle.  FIG. 15  is a polar radiation view illustrating the beam shape when the lamp has the lens that is made of PMMA.  FIG. 16  is cross-sectional view illustrating the beam shape when the lamp has the lens that is made of PMMA. In comparison with the lamp described in the first embodiment and shown in  FIG. 8  and  FIG. 9 , the lamp having the lens  300  described in this embodiment and shown in  FIG. 15  and  FIG. 16  has relatively uniform luminance within the range of the viewing angle, and the light with relatively uniform luminance can be emitted from the top of the lamp  200  (shown in  FIG. 4 ). 
     The first light incident surface described in the first and the second embodiments is an inclined surface or a plane, for instance. However, people having ordinary skill in the art are able to modify the shape of the lens of the invention, so as to satisfy the requirement for wide viewing angle, favorable beam shape, and desirable luminance. For instance, the first light incident surface can be the curved concave. 
     In the first embodiment and the second embodiment, the concave stands for curving toward the inside of the lens, and the convex stands for bulging toward the outside of the lens. However, people having ordinary skill in the art are aware that the concave and the convex are relative terms in the above embodiments and should not be construed as limitations to the descriptions in the embodiments or to the drawings. 
     In light of the foregoing, the lens of the invention has the simple look and is easy to make, and thus the manufacturing costs of the lens are rather low. Moreover, when the lens and the directional LED light source are both applied, the range of the viewing angle of the LED light source can be enlarged. As such, the LED light source can be used in the decorative lamp and can be extensively applied. 
     Although the invention has been described with reference to the above embodiments, it will be apparent to one of the ordinary skill in the art that modifications to the described embodiment may be made without departing from the spirit of the invention. Accordingly, the scope of the invention will be defined by the attached claims not by the above detailed descriptions.