Patent Publication Number: US-2015078009-A1

Title: Optical lens and light source module having the same

Description:
BACKGROUND 
     1. Technical Field 
     The disclosure generally relates to optical lenses, and particularly relates to an optical lens to increase an illuminating angle of a light source and a light source module having the optical lens. 
     2. Description of Related Art 
     In recent years, due to excellent light quality and high luminous efficiency, light emitting diodes (LEDs) have increasingly been used as substitutes for incandescent bulbs, compact fluorescent lamps and fluorescent tubes as light sources of illumination devices. 
     Generally, light intensity of a light emitting diode gradually decreases from a middle portion to lateral sides thereof. Such a feature makes the LED unsuitable for functioning as a light source which needs a uniform illumination, for example, a light source for a direct-type backlight module for a liquid crystal display (LCD). It is required to have an optical lens which can help the light emitted from a light emitting diode to have a wider illuminating angle and a uniform intensity. Unfortunately, the conventional optical lens and a light source module having the conventional optical lens can not obtain a satisfactory effectiveness. 
     What is needed, therefore, is an improved optical lens and a light source module having the optical lens to overcome the above described disadvantages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present embodiments 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 embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an isometric view of a light source module having an optical lens in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 2  is an inverted view of the optical lens of the light source module in  FIG. 1 . 
         FIG. 3  is a cross section view of the light source module in  FIG. 1 , taken along a line III-III thereof. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of an optical lens and a light source module will now be described in detail below and with reference to the drawings. 
     Referring to  FIGS. 1 through 3 , a light source module  100  in accordance with an exemplary embodiment of the disclosure is illustrated. The light source module  100  includes a light source  10  and an optical lens  20  covering the light source  10 . The optical lens  20  includes a light incident face  21  facing the light source  10 , a light emitting face  22  opposite to the light incident face  21 , and a connecting face  23  connecting the light incident face  21  and the light emitting face  22 . The light source  10  has an optical axis I, around which light emitted from the light source  10  concentrates in a surrounding space. 
     In this embodiment of the present disclosure, the light source  10  is a light emitting diode (LED), and includes a supporting base  12  and an LED chip  14  mounted on the supporting base  12 . The supporting base  12  is flat. The supporting base  12  may be made of electrically-insulating materials such as epoxy, silicon or ceramic. The LED chip  14  may be made of semiconductor materials such as GaN, InGaN, AlInGaN or the like. Preferably, the LED chip  14  emits visible light when being activated. 
     The optical lens  20  is integrally made of transparent materials such as PC (polycarbonate), PMMA (polymethyl methacrylate) or optical glass. It could be understood, a plurality of fluorescence, such as YAG, TAG, silicate, nitride, nitrogen oxides, phosphide, arsenide, telluride or sulfide, could be further provided to mix in the optical lens  20 . 
     The optical lens  20  is located above and spaced from the light source  10 . A center of a bottom face of the optical lens  20  is recessed inwardly, whereby the light incident face  21  and a receiving space  24  for accommodating the light source  10  are formed. The connecting face  23  is an annular and planar face surrounding the light incident face  21 . In use, the connecting face  23  is fitly attached on a supporting face (not shown) supporting the light source  10  and the optical lens  20 . The optical lens  20  defines a central axis X, and the optical lens  20  is rotationally symmetrical relative to the central axis X. The central axis X of the optical lens  20  is aligned with the optical axis I of the light source  10 . The light incident face  21  is a curved face and protrudes away from the light source  10 . The light incident face  21  is a sculptured face, an ellipsoidal face, a spherical face or a paraboloidal face. The light incident face  21  is rotationally symmetrical relative to the central axis X. The light emitting face  22  is rotationally symmetrical relative to the central axis X. 
     The light emitting face  22  includes a lateral face  222  extending upwardly from an outer periphery of the connecting face  23  and a top face  221  located above the light incident face  21 . The lateral face  222  is a cylindrical face. The top face  221  of the light emitting face  22  includes a center facet  2210  facing the light incident face  21 , a first curved facet  2211  surrounding and connecting to the center facet  2210 , and a second curved facet  2212  surrounding and smoothly connecting to the first curved facet  2211 . The first curved facet  2211  is sculptured, ellipsoidal, spherical or paraboloidal. The first curved facet  2211  is rotationally symmetrical relative to the central axis X. The first curved facet  2211  protrudes toward the light incident face  21 . The second curved facet  2212  protrudes away from the light incident face  21 . The second curved facet  2212  is sculptured, ellipsoidal, spherical or paraboloidal. The second curved facet  2212  is rotationally symmetrical relative to the central axis X. An outer periphery of the second curved facet  2212  of the light emitting face  22  correspondingly meets the lateral face  222 . The center facet  2210  of the top face  221  is planar or concave. The center facet  2210  is rotationally symmetrical relative to the central axis X. 
     In use, the light emitted from the light source  10  is entered into the optical lens  20  through the light incident face  21  and refracted, then transmitted in the optical lens  20 , and exited and refracted from the center facet  2210 , the first curved facet  2211  and the second curved facet  2212  of the top face  221 , and the lateral face  222 . The light is gradually diverged relative to the optical axis I of the optical lens  20 , thus an illumination angle of the light source module  100  is widened and whereby the light source module  100  can illuminate more evenly. 
     It is to be further understood that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.